Brain Grain · braingrain.in
Physics — Practice Paper · Set 1
Class: 11Samacheer KalviMax Marks: 93
Name: ____________________Reg No: ____________
Part I — Multiple Choice Questions 15 × 1 = 15
Choose the correct answer. (Answer all questions.)
1.From a thin uniform disc of radius 2R, another disc of diameter 2R is removed. The mass of the remaining portion is m. Find the moment of Inertia of the shaded portion about an axis passing through 0 and perpendicular to the plane. a) \(\frac{8 M R^{2}}{13}\) b) \(\frac{ M R^{2}}{6}\) c) \(\frac{13 M R^{2}}{6}\) d) \(\frac{8 M R^{2}}{6}\)[1]
2.If a particle executes uniform circular motion in the XY plane in a clockwise direction, then the angular velocity is in _______. a) +y direction b) +z direction c) -z direction d) -x direction[1]
3.A man sitting on a swing which is moving to an angle of 60° from the vertical is blowing. a whistle which has a frequency of 2.0 k Hz. The whistle is 2.0 m from the fixed support point of the swing. A sound detector which detects the whistle sound is kept in front of the swing. The maximum frequency the sound detector detected is:(a) 2.027 kHz(b) 1.914 kHz(c) 9.14 kHz(d) 1.011 kHz[1]
4.Six vectors \(\vec{a}\) through \(\vec{f}\) have magnitudes and directions as indicated in figure. Which of the following statement is true? a) \(\overline{b}\) + \(\overline{e}\) = \(\overline{f}\) b) 3\(\hat{i}\) – 2\(\hat{j}\) + \(\hat{k}\) \(\hat{b}\) + \(\hat{c}\) = \(\hat{f}\) c) \(\hat{d}\) + \(\hat{c}\) = \(\hat{f}\) d) \(\hat{d}\) + \(\hat{e}\) = \(\hat{f}\)[1]
5.If the mass and radius of the Earth are both doubled, then the acceleration due to gravity g’: (a) remains same (b) y (c) \(\frac { g }{ 2 }\) (d) 4 g[1]
6.A ball moving with a certain velocity hits another identical ball at rest. If the plane is frictionless and collision is elastic, the angle between the directions in which the balls move after collision will be _______. a) 30° b) 60° c) 90° d) 120°[1]
7.The dimensionless quantity _______.(a) never has a unit(b) always has a unit(c) may has a unit(d) does not exist[1]
8.When a uniform rod is heated, which of the following quantity of the rod will increase:(a) mass(b) weight(c) centre of mass(d) moment of inertia[1]
9.The dimensions of mobility are _______(a) M -1 LA T -2(b) ML A -1 T -2(c) MA -1 T -2(d) M -1 A T 2[1]
10.The damping force on an oscillator is directly proportional to the velocity. The units of the constant of proportionality are: (AIPMT 2012)(a) kg m s -1(b) kg m s -2(c) kg s -1(d) kg s[1]
11.If a person moving from pole to equator, the centrifugal force acting on him a) increase b) decreases c) remains the same d) increase and then decreases[1]
12.The frequency of vibration of string is given by γ l = \(\frac{p}{2 \ell} \sqrt{\frac{T}{m}}\) Here l is the length, P is the number of segments in the string. T is tension is the string, the dimensional formula for ‘m’ will be. (a) M 0 L T -1 (b) M L 0 T -1 (c) M L -1 T 0 (d) M 0 L 0 T 0[1]
13.The dimension of (µ 0 ε 0 ) \(\frac { -1 }{ 2 }\) is _____________. [Main AIPMT 2011] (a) length (b) time (c) velocity (d) force[1]
14.Which one of the following quantities cannot be represented by a scalar? a) Mass b) length c) momentum d) magnitude of the acceleration[1]
15.A particle of mass m is moving with speed u in a direction which makes 60° with respect to x-axis. It undergoes elastic collision with the wall. What is the change in momentum in x and y direction?(a) ∆p x = – mu, ∆p y = 0(b) ∆p x = – 2mu, ∆p y = 0(c) ∆p x = 0, ∆p y = mu(d) ∆p x = mu, ∆p y = 0[1]
Part II — Short Answer Questions 14 × 2 = 28
Answer briefly. (Answer all questions.)
16.What is meant by the force constant of a spring?[2]
17.If the acceleration due to gravity becomes 4 times of original value, then escape speed: (a) remains same is directly proportional to the product of (b) 2 times of original value masses and inversely proportional to square (c) becomes halved of the distance between the masses. (d) 4 times of original value 3. Will the angular momentum of a planet be[2]
18.An object is thrown with initial speed of 5ms -1 with an angle of projection of 30°. What is the height and range reached by the particle?[2]
19.Define one mole.[2]
20.State the equation of state for an isothermal process.[2]
21.What is the relation between the average kinetic energy and pressure?[2]
22.The time period for small vertical oscillations of block of mass m when the masses of the pulleys are negligible and spring constant k 1 and k 2 is: (a) T = 4π\(\sqrt{m\left(\frac{1}{k_{1}}+\frac{1}{k_{2}}\right)}\) (b) T = 2π\(\sqrt{m\left(\frac{1}{k_{1}}+\frac{1}{k_{2}}\right)}\) (c) T = 4π\(\sqrt{m\left(k_{1}+k_{2}\right)}\) (d) T = 2π\(\sqrt{m\left(k_{1}+k_{2}\right)}\)[2]
23.What are the factors affecting the surface tension of a liquid?[2]
24.Consider the Earth as a homogeneous sphere of radius R and a straight hole is bored in it through its centre. Show that a particle dropped into the hole will execute a simple harmonic motion such that its time Period is T = 2π\(\sqrt{\frac{\mathrm{R}}{g}}\)[2]
25.State Newton’s Universal law of gravitation.[2]
26.When a damped harmonic oscillator completes 100 oscillations, its amplitude is reduced to\(\frac { 1 }{ 3 }\) of its initial value. What will be its amplitude when it completes 200 oscillations? (a) \(\frac { 1 }{ 5 }\) (b) \(\frac { 2 }{ 3 }\) (c) \(\frac { 1 }{ 6 }\) (d) \(\frac { 1 }{ 9 }\)[2]
27.A piece of wood of mass m is floating erect in a liquid whose density is ρ. If it is slightly pressed down and released, then executes simple harmonic motion. Show that its time period of oscillation is T = 2π\(\sqrt{\frac{m}{\mathrm{Ag} \rho}}\)[2]
28.State an equation state for an isochoric process.[2]
29.Two particles P and Q of mass 1 kg and 3 kg respectively start moving towards each other from rest under mutual attraction. What is the velocity of their center of mass?[2]
Part III — Long Answer Questions 10 × 5 = 50
Answer in detail. (Answer all questions.)
30.What is the microscopic origin of T is uniformly distributed to all degrees of temperature?[5]
31.What are concurrent forces? State Lamis theorem.[5]
32.Explain the need for banking of tracks.[5]
33.Why the passengers are advised to remove the ink from their pens while going up in an aeroplane?[5]
34.Briefly explain the types of physical quantities?[5]
35.Define the following[5]
36.A uniform rod of mass m and length l makes a constant angle θ with an axis of rotation which passes through one end of the rod. Find the moment of Inertia about this axis.[5]
37.Define center of gravity.[5]
38.What do you mean by capillarity or capillary action?[5]
39.Write short notes on reflection of sound waves from plane and curved surfaces.[5]
🔑 Show Answer Key — Set 1
- 1. c) \(\frac{13 M R^{2}}{6}\)
- 2. c) -z direction
- 3. (a) 2.027 kHz Hint:
- 4. d) \(\hat{d}\) + \(\hat{e}\) = \(\hat{f}\)
- 5. (b) y Hint: g = \(\frac{\mathrm{GM}}{\mathrm{R}^{2}}\) M’ = 2M R’ = 2R g’ = \(\frac{\mathrm{GM}^{\prime}}{\left(\mathrm{R}^{\prime}\right)^{2}}\) = \(\frac{G \times 2 M}{(2 R)^{2}}\) = \(\frac{\mathrm{GM}}{\mathrm{2R}^{2}}\) = \(\frac { g }{ 2 }\)
- 6. c) 90°
- 7. (c) may has a unit
- 8. (d) moment of inertia Hint: M.I. = MK² K – radius of gyration. During heating K would be increased. Hence moment of inertia will increase.
- 9. (d) M -1 A T 2
- 10. (c) kg s -1 Hint: F d ∝ v F d = – bv F d = kv ∴ k = \(\frac{\mathrm{F}_{d}}{\nu}\) Units of k = \(\frac{\mathrm{kgms}^{-2}}{\mathrm{~m} / \mathrm{s}}\) = kg -1 Units of proportionality constant = kgs -1
- 11. a) increase II. Short Answer Questions:
- 12. (c) M L -1 T 0
- 13. (c) velocity
- 14. c) momentum
- 15. (a) ∆p x = – mu, ∆p y = 0 Hint: As it moves with respect to X axis ∆p x = – mu ∆p y = 0
- 16. Force constant is defined as force per unit length.
- 17. (b) 2 times of original value masses and inversely proportional to square
- 18. u = 5 m/s θ = 30° h max = ? R = ? Height reached Range:
- 19. One mole of any substance is the amount of that substance which contains Avogadro number (NA) of particles (such as atoms or molecules).
- 20. The equation of state for isothermal process is given by, PV = constant
- 21. P = \(\frac {2}{ 3 }\)\(\overline{KE}\)
- 22. (a) T = 4π\(\sqrt{m\left(\frac{1}{k_{1}}+\frac{1}{k_{2}}\right)}\) Hint: T = 2π\(\frac { m }{ k }\) The given arrangement is similar to the combination of springs in series.
- 23. The presence of any contamination or impurities. The presence of dissolved substances. Electrification Temperature
- 24. (Here, negative has no meaning. It can be neglected) Comparing equation (1) & (2) we get, Time period, T = 2π\(\sqrt{\frac{\mathrm{R}}{g}}\) Hence proved.
- 25. The gravitational force between two masses is directly proportional to the product of masses and inversely proportional to square of the distance between the masses.
- 26. (b) \(\frac { 2 }{ 3 }\) Hint:
- 27. When a wood is pressed and released,
- 28. The equation of state for an isochoric process is given by, P = (\(\frac { μR }{ V }\))T
- 29. Since external force acting as them is zero, the velocity of cm is constant and hence Vcm =0, whenever the separation.
- 30. The average K.E per molecule \(\overline{\mathrm{KE}}=\epsilon=\frac{3}{2} k \mathrm{T}\) The equation implies that the temperature of a gas is a measure of the average translational K.E. per molecule of the gas.
- 31. Concurrent forces: A collection of forces is said to be concurrent if the lines of forces act at a common point. If the concurrent forces are in same plane they are coplanar also, in additional to concurrent forces. Lamis is a theorem: If a system of three concurrent and coplanar forces is in equilibrium, then Lamis theorem states that ” the magnitude of each force of the system is proportional to sine of the angle between other two forces”. Proof: Let F1, F2 and F3 be three coplanar and concurrent forces act at a common point 0 as in figure. If the point 0 is in equilibrium then according to Lamis theorem.
- 32. In a leveled circular road skidding mainly depends on the co-efficient of static friction n s. The coefficient of static friction depends on the nature of surface which has a maximum limiting value. To avoid this usually “the outer edge of the road is slightly raised compared to inner edge”. This is called banking of roads or tracks. The angle of inclination called banking angle. Let the surface of the road make angle θ with horizontal surface. Then the normal force makes an angle θ with vertical. When the car takes a turn, two forces are acting on the car. (a) Gravitational force mg (downwards) (b) Normal force N (Perpendicular to surface). Normal force ‘N’ can be resolved into two compo…
- 33. While going up in an aeroplane the atmospheric pressure decreases with height. When aeroplane is going up, the ink in the pen tends to ooze out to equalise the pressure. This may spoil the clothes of the passengers. So they are advised to remove ink from the pen.
- 34. Physical quantities are classified into two types. There are fundamental and derived quantities. Fundamental or base quantities are quantities which cannot be expressed in terms of any other physical quantities. These are length, mass, time, electric current, temperature, luminous intensity, and amount of substance. Quantities that can be expressed in terms of fundamental quantities are called derived quantities. For example, area, volume, velocity, acceleration, force.
- 35. a) Coefficient of restitution b) Power c) Law of conservation of energy d) Loss of Kinetic energy in inelastic collision a) Coefficient of restitution: Coefficient of restitution defined as the ratio of velocity of separation (after collision) to velocity of approach (before collision) The coefficient of restitution = b) Power: Power is defined as the rate of work done or energy delivered P = \(\frac { W }{ t }\) = \(\vec{F}\).\(\vec{V}\) c) Law of conservation of energy: Law states that “Energy can neither be created nor destroyed. It may be transformed from one to another but the total energy of an isolated system remains constant” d) Loss of kinetic energy in inelastic collision The di…
- 36. Here mass is distributed on length taking an element of small length dx at a distance x as in figure. dm = \(\frac{\mathrm{M}}{\ell}\).dx Moment of Inertia of small element
- 37. The center of gravity of a body is the point at which the entire weight of the body acts, irrespective of the position and orientation of the body.
- 38. In a liquid whose angle of contact with solid is less than 90°, suffers capillary rise. On the other hand, in a liquid whose angle of contact is greater than 90°, suffers capillary fall. The rise or fall of a liquid in a narrow tube is called capillarity or capillary action.
- 39. When the sound waves hit the plane wall, they bounce off in a manner similar to that of light. When a loudspeaker is kept at an angle with respect to a wall (plane surface), then the waves coming from the source (assumed to be a point source) can be treated as spherical wave fronts. Hence, the reflected wave front on the plane surface is also spherical, such that its centre of curvature can be treated as the image of the sound source (virtual or imaginary loud speaker) that can be assumed to be at a position behind the plane surface. These are shown in figures. The behaviour of sound is different when it is reflected from different surfaces-convex or concave or plane. The sound reflected…
Brain Grain · braingrain.in
Physics — Practice Paper · Set 2
Class: 11Samacheer KalviMax Marks: 93
Name: ____________________Reg No: ____________
Part I — Multiple Choice Questions 15 × 1 = 15
Choose the correct answer. (Answer all questions.)
1.Two masses m 1 and m 2 are connected by a light string passing over a smooth pulley. When set free m 1 moves down by 2m in 2s the ratio of m 1 /m 2 is _______. a) 9/7 b) 11/ 9 c) 13/11 d) 15/13[1]
2.If an elevator moving vertically up with an acceleration g, the force entered on the floor by a passenger of mass M is _______. a) mg b) 1 / 2 mg c) zero d) 2 mg[1]
3.With an increase in temperature, the viscosity of liquid and gas, respectively will:(a) increase and increase(b) increase and decrease(c) decrease and increase(d) decrease and decrease[1]
4.If \(\overrightarrow{\mathrm{A}}\) and \(\overrightarrow{\mathrm{B}}\) are two vectors, which are acting along x, y respectively, then \(\overrightarrow{\mathrm{A}}\) and \(\overrightarrow{\mathrm{B}}\) lies along- (a) x (b) y (c) z (d) none[1]
5.A force vector applied on a mass is represented as \(\vec { f }\) = 6\(\vec { i }\) – 8\(\vec { j }\) + 10\(\vec { k }\) and accelerates with 1ms -2, what will be the mass of the body in kg _______. a) 10\(\sqrt{2}\) b) 20 c) 2\(\sqrt{10}\) d) 10[1]
6.Newton’s second law gives – (a) \(\overrightarrow{\mathrm{F}} \propto \frac{d \overrightarrow{\mathrm{P}}}{\mathrm{dt}}\) (b) \(\overrightarrow{\mathrm{F}}=\frac{d \overrightarrow{\mathrm{P}}}{\mathrm{dt}}\) (c) \(\overrightarrow{\mathrm{F}}=m \vec{a}\) (d) all the above[1]
7.A uniform force of (2\(\hat{i}\) + \(\hat{j}\)) N acts on a particle of mass 1 kg. The particle displaces from position (3\(\hat{j}\) + \(\hat{k}\) )m to (5\(\hat{i}\) + 3\(\hat{j}\)) m. The work done by the force on the particle is _______. (AIPMT Model 2013) a) 9 J b) 6 J c) 10 J d) 12 J[1]
8.From a circular disc of mass M and radius R a part of 60° is removed. The M.I of the remaining portion of disc about an axis passing through the center and perpendicular to the plane of disc is _______. a) 5/6 MR² b) 5/12 MR² c) 5/3 MR² d) 5/24 MR²[1]
9.A pendulum is hung in a very high building oscillates to and fro motion freely like a simple harmonic oscillator. If the acceleration of the bob is 16 ms -2 at a distance of 4 m from the mean position, then the time period is: (NEET 2018 model)(a) 2s(b) 1s(c) 2 πs(d) πs[1]
10.If an object is dropped from the top of a building and it reaches the ground at t = 4s, then the height of the building is (ignoring air resistance) (g = 9.8ms -2 ) a) 77.3m b) 78.4m c) 80.5 d) 79.2m[1]
11.When a cycle tyre suddenly bursts, the air inside the tyre expands. This process is:(a) isothermal(b) adiabatic(c) isobaric(d) isochoric[1]
12.Two blocks of mass m 1 6 kg and m 2 = 3 kg as in figure coefficient of friction between m 1, and m 2 and between m 1 and surface is 0.5 and 0.4 respectively. The maximum horizontal force to can be applied to the mass m 1 so that they move without separation is _______. a) 41 N b) 61 N c) 81 N d) 101 N[1]
13.Four identical blocks each of mass m linked by threads as shown. IF the system moves with constant acceleration under the influence of force F, the Tension T 2 _______. a) F b) F/2 c) 2F d) F/4[1]
14.The centrifugal force appears to exist _______. a) only in inertial frames b) only in rotating frames c) in an accelerated frame d) both in inertial and non-inertial frames[1]
15.The length, breadth and thickness of strip are given by l = (10.0±0.1)cm, h=(1.00±0.01)cm t = (0.100±0.001)cm the most probable error in volume will be _______(a) 0.03 cm 3(b) 0.111 cm 3(c) 0.012 cm 3(d) 0.12 cm 3[1]
Part II — Short Answer Questions 14 × 2 = 28
Answer briefly. (Answer all questions.)
16.Imagine that the gravitational force between Earth and Moon is provided by an invisible string that exists between the Moon and Earth. What is the tension that, exists in this invisible string due to earth’s centripetal force?[2]
17.In an adiabatic expansion of the air, the volume is increased by 4%, what is percentage change in pressure? (For air γ = 1.4)[2]
18.Define a vector. Give Example.[2]
19.Four particles, each of mass M and equidistant from each other, move along a circle of radius R under the action of their mutual gravitational attraction. Calculate the speed of each particle.[2]
20.Define the gravitational field. Give its unit.[2]
21.Convert the vector \(\overline{r}\) = 3\(\hat{i}\) + 2\(\hat{j}\) into a unit vector.[2]
22.Give any two examples of torque in day-to-day life.[2]
23.What is meant by ‘thermal equilibrium’?[2]
24.If an object is thrown horizontally with an initial speed 10 ms -1 from the top of a building of height 100 m. What is the horizontal distance covered by the particle?[2]
25.Can a body have a constant speed and still have varying velocity?[2]
26.Define Poisson’s ratio.[2]
27.People often say “for every action there is an equivalent opposite reaction”. Here they meant ‘action of a human’. Is it correct to apply Newton’s third law to human actions? What is mean by ‘action’ in Newton’s third law? Give your arguments based on Newton’s laws.[2]
28.An ideal spring of spring constant k, is suspended from the ceiling of a room and a block of mass m is fastened to its lower end. If the block is released when the spring is un-stretched, then the maximum extension in the spring is: (a) 4\(\frac { mg }{ k }\) (b) \(\frac { mg }{ k }\) (c) 2\(\frac { mg }{ k }\) (d) \(\frac { mg }{ 2k }\)[2]
29.What is a black body?[2]
Part III — Long Answer Questions 10 × 5 = 50
Answer in detail. (Answer all questions.)
30.In a submarine equipped with sonar the time delay between the generation of a pulse and its echo after reflection form an enemy submarine is observed to be 80s. If the speed of sound in water is 1460 ms -1. What is the distance of enemy submarine?[5]
31.What are the conditions in which force cannot produce torque?[5]
32.Explain Joule’s Experiment of the mechanical equivalent of heat.[5]
33.What are geostationary and polar satellites?[5]
34.State the principle and usage of Venturimeter.[5]
35.State the laws of simple pendulum.[5]
36.Distinguish between cohesive and adhesive forces.[5]
37.State the law of floatation.[5]
38.Why is the energy of a satellite (or any other planet) negative?[5]
39.Consider a mixture of 2 mol of helium and 4 mol of oxygen. Compute the speed of sound in this gas mixture at 300 K.[5]
🔑 Show Answer Key — Set 2
- 1. b) 11/ 9
- 2. d) 2 mg
- 3. (c) decrease and increase
- 4. (c) z
- 5. a) 10\(\sqrt{2}\)
- 6. (d) all the above
- 7. c) 10 J
- 8. b) 5/12 MR²
- 9. (d) πs Hint: a = 16 m/s²; y = 4 a = – \(\frac { g }{ l }\)x = – ω²x 16 = \(\left|1-\omega^{2} \times 4\right|\) ∴ ω² = \(\frac { 16 }{ 4 }\) = 4 ω = 2 Time period T = \(\frac { 2π }{ ω }\) = πs
- 10. b) 78.4m
- 11. (b) adiabatic
- 12. c) 81 N
- 13. b) F/2
- 14. b) only in rotating frames
- 15. (a) 0.03 cm 3
- 16. Mass of moon = 7.34 x 10 22 kg Distance between the moon and earth = 3.84 x 10 8 m
- 17. Percentage of increased volume = 4% \(\frac { ∆V }{ V }\) x 100 = 4% γ = 1.4 In adiabatic process PV γ = Constant
- 18. Vector is a quantity which is described by both magnitude and direction. Geometrically a vector is a directed line segment. Example – force, velocity, displacement.
- 19. Force acting on a particle Since particle, moving circular path experience centripetal force,
- 20. The gravitational field intensity \(\overrightarrow{\mathrm{E}}_{1}\) at a point is defined as the gravitational force experienced by unit mass at that point. It’s unit N kg -1.
- 21. A vector divided by its magnitude is a unit vector
- 22. The opening and closing of a door about the hinges. Turning of a nut using a wrench.
- 23. Two systems are said to be in thermal equilibrium with each other if they are at the same temperature, which will not change with time.
- 24. u = 10 m/s h = 100 m x = ? x = u x T x = 45.18 m.
- 25. Yes, a particle in uniform circular motion has a constant speed but varying velocity because of the change in its direction of motion at every point.
- 26. It is defined as the ratio of relative contraction (lateral strain), to relative expansion (longitudinal strain).
- 27. Newton’s third law is applicable to only humans actions that involve physical force. Third law is not applicable to humans’ psychological actions or thoughts.
- 28. (c) 2\(\frac { mg }{ k }\) Hint:
- 29. A black body is one which neither reflects nor transmits but absorbs whole of the radiation incident on it.
- 30. Time taken = 80s Velocity of sound = V = 1460 m/s Distance of enemy submarine d = ? V = \(\frac{2d}{t}\) d = \(\frac{Vt}{2}\) = \(\frac{1460×80}{2}\) = 1460 x 40 = 58400 m d = 58.4k m
- 31. 1) The torque is zero when r and P are either parallel or anti parallel i.e θ = 0, if parallel sin θ = 0, τ = 0 θ = 180°, if anti parallel sin 180 = 0, τ = 0 2) The torque is zero if the force acts at the reference point as \(\vec { r }\) = 0, τ = 0
- 32. Joule showed that mechanical energy can be converted into internal energy and vice versa. In his experiment, two masses were tied with a rope and a paddle wheel as shown in Figure. When these masses fall through a distance h due to gravity, both the masses lose potential energy which is equal to 2mgh. When the masses fall, the paddle wheel turns. Due to the turning of wheel inside water, frictional force comes in between the water and the paddle wheel. This causes a rise in temperature of the water. This confirms that gravitational potential energy is converted to internal energy of water. The temperature of water increases due to the work done by the masses. In fact, Joule was able to sh…
- 33. Geostationary Satellite: It is the satellite which appears at a fixed position and at a definite height to an observer on earth. Polar Satellite: It is the satellite which revolves in polar orbit around the earth.
- 34. This device is used to measure the rate of flow (or say flow speed) of the incompressible fluid flowing through a pipe. It works on the principle of Bernoulli’s theorem. III. Long Answer Questions:
- 35. Laws of simple pendulum: The time period of a simple pendulum. Depends on the following laws: (i) Law of length: For a given value of acceleration due to gravity, the time period of a simple pendulum is directly proportional to the square root of length of the pendulum. T ∝ \(\sqrt{l}\) … (1) (ii) Law of acceleration: For a fixed length, the time period of a simple pendulum is inversely proportional to the square root of acceleration due to gravity. T ∝ \(\frac{1}{\sqrt{g}}\) … (2)
- 36. Cohesive – The force between the like molecules which holds the liquid together is called ‘cohesive force’. Adhesive – When the liquid is in contact with a solid, the molecules of these solid and liquid will experience an attractive force which is called ‘adhesive force’.
- 37. The law of floatation states that a body will float in a liquid if the weight of the liquid displaced by the immersed part of the body equals the weight of the body.
- 38. The negative sign of the total energy implies that satellite is bound to the Earth’s gravitational force. So it cannot escape from the Earth. At large distances satellite is not bound to Earth. It is completely free from gravitational force of the Earth.
- 39. Number of molecules of helium = 2 Number of molecules of oxygen = 4 When helium and oxygen are mixed, hence the molecular weight of the mixture of gases is given by In addition, helium is monoatomic, \(\mathrm{C}_{v_{2}}\) = \(\frac { 2R }{ 2 }\) Oxygen is diatomic \(\mathrm{C}_{v_{1}}\) = \(\frac { 5R }{ 2 }\) Ratio of specific heat capacitors of a mixture of gases is According to Laplace, the speed of sound in a gas is ∴ The speed of sound = 400.9 m/s
Brain Grain · braingrain.in
Physics — Practice Paper · Set 3
Class: 11Samacheer KalviMax Marks: 93
Name: ____________________Reg No: ____________
Part I — Multiple Choice Questions 15 × 1 = 15
Choose the correct answer. (Answer all questions.)
1.\(\overrightarrow{\mathrm{A}}\) x \(\overrightarrow{\mathrm{B}}\) isequal to – (a) \(\overrightarrow{\mathrm{B}}\) x \(\overrightarrow{\mathrm{A}}\) (b) \(\overrightarrow{\mathrm{A}}\) + \(\overrightarrow{\mathrm{B}}\) (c) –\(\overrightarrow{\mathrm{B}}\) x \(\overrightarrow{\mathrm{A}}\) (d) \(\overrightarrow{\mathrm{A}}\) – \(\overrightarrow{\mathrm{B}}\)[1]
2.The resistance of a conductor R = V/I where v = (50±2)v and I = (9 ± 0.3) A find the percentage error in R.(a) 8.5%(b) 3.7%(c) 7.8%(d) 7.3%[1]
3.A body of 5 kg is moving with a velocity of 20m/s. If a force of 100 N is applied on it for 10s in the same direction as its velocity, what will now be the velocity of the body _______. a) 2000 m/s b) 220 m/s c) 240 m/s d) 260 m/s[1]
4.The center of mass of a system of particles does not depend upon, _______. [AIPMT 1997, AIEEE 2004] a) position of particles b) relative distance between particles c) masses of particles d) force acting on particle[1]
5.The scalar product \(\overrightarrow{\mathrm{A}}\).\(\overrightarrow{\mathrm{B}}\)is equal to- (a) \(\overrightarrow{\mathrm{A}}\) +\(\overrightarrow{\mathrm{B}}\) (b) \(\overrightarrow{\mathrm{A}}\). \(\overrightarrow{\mathrm{B}}\) (c) AB sin θ (d) (\(\overrightarrow{\mathrm{A}}\) x \(\overrightarrow{\mathrm{B}}\)[1]
6.A 2kg block slides on a horizontal floor with a speed of 4 m/s. It strikes on uncompressed spring and compresses it fill the block is motionless. The kinetic friction force is 15N and spring constant is 10 4 N/m. The spring compress by _______. a) 5.5 cm b) 2.5 cm c) 11 cm d) 8.5 cm[1]
7.One astronomical unit is equal to _______.(a) 1.510 x 10 12 m(b) 1.5 x 10 12 Km(c) 1.5 x 10 11 m(d) 1.5 x 10 12 Cm[1]
8.A ball of mass 200g is attached to a string 50 mm and a force F is applied as shown. The W.D by this force if the string makes an angle 60° with vertical is? [at initial and final positions speed of the ball is zero.] a) 1J b) 0.5J c) 0.05J d) 0.25J[1]
9.Three thin, uniform, identical rods each of mass M and length L are Joined as shown. The moment of inertia about an axis passing through 0 and perpendicular to plane is _______. a) 3ML² b) ML² c) \(\frac{M L^{2}}{3}\) d) zero[1]
10.A container has one mole of monoatomic ideal gas. Each molecule has f degrees of freedom. What is the ratio of γ = \(\frac{\mathrm{C}_{\mathrm{P}}}{\mathrm{C}_{\mathrm{V}}}\)? (a) f (b) \(\frac { f }{ 2 }\) (c) \(\frac { f }{ f + 2 }\) (d) \(\frac { f+2 }{ f }\)[1]
11.Two wires are made of the same material and have the same volume. The area of cross sections of the first and the second wires are A and 2A respectively. If the length of the first wire is increased by Δl on applying a force F, how much force is needed to stretch the second wire by the same amount? [NEET model 2018](a) 2(b) 4(c) 8(d) 16[1]
12.The vector product of any two vectors gives a – (a) vector (b) scalar (e) tensor (d) col-linear[1]
13.The length of a second’s pendulum on the surface of the Earth is 0.9 m. The length of the same pendulum on the surface of planet X such that the acceleration of the planet X is n times greater than the Earth is: (a) 0.9 n (b) \(\frac { 0.9 }{ n }\)m (c) 0.9 n²m (d) \(\frac{0.9}{n^{2}}\)[1]
14.Center of mass may lie- (a) within the body (b) outside the body (c) both (a) and (b) (d) only at the center[1]
15.The velocity of a particle v at an instant t is given by v = at + bt² the dimension of b is _____________(a) [L](b) [LT -1 ](c) [LT -2 ](d) [LT -3 ][1]
Part II — Short Answer Questions 14 × 2 = 28
Answer briefly. (Answer all questions.)
16.Why coffee runs up into a sugar lump (a small cube of sugar) when one corner of the sugar lump is held in the liquid?[2]
17.Three identical solid spheres move down through three inclined planes A, B, and C all same dimensions. A is without friction, B is undergoing pure rolling and C is rolling with slipping compare the kinetic energies E A, E B and E c at the bottom.[2]
18.A simple pendulum has a time period T 1. When its point of suspension is moved vertically upwards according as y = kt², where y is vertical distance covered and k = 1 ms -2, its time period becomes T 2. Then, \(\frac{\mathrm{T}_{1}^{2}}{\mathrm{~T}_{2}^{2}}\) is (g = 10 ms -2 (a) \(\frac { 5 }{ 6 }\) (b) \(\frac { 11 }{ 10 }\) (c) \(\frac { 6 }{ 5 }\) (d) \(\frac { 5 }{ 4 }\)[2]
19.A certain number of spherical drops of a liquid of radius R coalesce to form a single drop of radius R and volume V If T is the surface tension of the liquid, then: (a) energy = 4VT(\(\frac { 1 }{ r }\) – \(\frac { 1 }{ R }\)) is released (b) energy = 3 VT(\(\frac { 1 }{ r }\) + \(\frac { 1 }{ R }\)) is absorbed (c) energy = 3VT (\(\frac { 1 }{ r }\) – \(\frac { 1 }{ R }\))is released (d) energy is neither released nor absorbed[2]
20.Define one newton:[2]
21.In the planet Mars, the average temperature is around – 53°C and atmospheric pressure is 0.9 kPa. Calculate the number of moles of the molecules in unit volume in the planet Mars? Is this greater than that in earth?[2]
22.State Newton’s third law.[2]
23.What are longitudinal waves? Give one example.[2]
24.Find out the center of mass for the given geometrical structures.[2]
25.Give the equation of state for an adiabatic process.[2]
26.Give the expression for work done by the gas.[2]
27.Write down the difference between simple harmonic motion angular simple harmonic motion.[2]
28.Two streamlines cannot cross each other. Why?[2]
29.What is the relation between torque and angular momentum?[2]
Part III — Long Answer Questions 10 × 5 = 50
Answer in detail. (Answer all questions.)
30.Define the quasi-static process.[5]
31.Two identical water bottles one empty and the other filled with water are allowed to roll down an inclined plane. Which one of them reaches the bottom first? Explain.[5]
32.A ship in a sea sends SONAR waves straight down into the seawater from the bottom of the ship. The signal reflects from the deep bottom bedrock and returns to the ship after 3.5 s. After the ship moves to 100 km it sends another signal which returns back after 2 s. Calculate the depth of the sea in each case and also compute the difference in height between two cases.[5]
33.Why is it much easier to balance a meter scale on your fingertip than balancing on a match stick?[5]
34.Derive the expression for the terminal velocity of a sphere moving in a high viscous fluid using stokes force.[5]
35.Explain the characteristics of elastic and inelastic collision Elastic collision:[5]
36.Write a Short note on vector product between two vectors.[5]
37.Write the rules for determining significant figures.[5]
38.Why does a porter bend forward while carrying a sack of rice on his back?[5]
39.Explain resonance. Give an example.[5]
🔑 Show Answer Key — Set 3
- 1. (c) –\(\overrightarrow{\mathrm{B}}\) x \(\overrightarrow{\mathrm{A}}\)
- 2. (d) 7.3%
- 3. b) 220 m/s
- 4. d) force acting on particle
- 5. (b) \(\overrightarrow{\mathrm{A}}\). \(\overrightarrow{\mathrm{B}}\)
- 6. a) 5.5 cm
- 7. (c) 1.5 x 10 11 m
- 8. b) 0.5J
- 9. b) ML²
- 10. (d) \(\frac { f+2 }{ f }\)
- 11. (b) 4
- 12. (a) vector
- 13. (a) 0.9 n Hint:
- 14. (c) both (a) and (b)
- 15. (d) [LT -3 ]
- 16. Dip the comer of a sugar cube in coffee, and get the whole cube coffee-flavoured due to “capillary action”.
- 17. A possesses translational K.E B possesses sum of rotational K.E + Translational K.E C possesses more rotation than translational KE
- 18. (c) \(\frac { 6 }{ 5 }\) Hint:
- 19. (c) energy = 3VT (\(\frac { 1 }{ r }\) – \(\frac { 1 }{ R }\))is released
- 20. One newton is defined as the force which acts on 1 kg of mass to give an acceleration 1 ms -2 in the direction of the force.
- 21. = 0.9 x 10³Pa PV = NkT Since volume is unity V = 1 Equation (1) becomes P = NkT Where k is Boltzmann constant
- 22. Newton’s third law states that for every action there is an equal and opposite reaction.
- 23. The direction of vibration of particles in a medium is parallel to the direction of propagation of the wave. Example: Sound waves traveling in air.
- 24. b) Cylinder: The center of mass in case of the cylinder lies on the vertical axis and at the centre of the cylinder.
- 25. The equation of state for an adiabatic proc ess is given by, PV γ = Constant
- 26. In general, the work done by the gas by increasing the volume from V i to V f is given by W = \(\int_{V_{i}}^{V_{f}} \mathrm{P} d \mathrm{~V}\)
- 27. Comparison of simple harmonic motion and angular simple harmonic motion.
- 28. If two streamlines cross each other, there will be two directions of flow at the point of intersection which is impossible.
- 29. Rate of change in angular momentum is equal to torque. τ = \(\frac { d(L) }{ dt }\)
- 30. A quasi-static process is an infinitely slow process in which the system changes its variables (P, V, T) so slowly such that it remains in thermal, mechanical, and chemical equilibrium with its surroundings throughout.
- 31. Empty water bottle has large moment of Inertia than filled water bottle. So least value of radius of gyration is for bottle filled with water. So the water bottle filled with water reaches bottom first. Suggests that for a given angle of inclination, the object with least value of radius of gyration k reach the bottom of incline first.
- 32. In the first case time = 3.5s Velocity sound in sea water = 1450 m/s Distance 2d = v x t = 1450 x 3.5 = 5,075 m Depth of the sea d = \(\frac { 5075 }{ 2 }\) = 2537.5 m In the second case, time = 2s Velocity of sound in water = 1450 m/s Distance 2d = vt = 1450 x 2 = 2900 m Depth of the sea d = \(\frac { 2900 }{ 2 }\) = 1450 Difference ∆d = 2537.5 – 1450 = 1087.5 = 1087.5 m
- 33. It is much easier to balance a meter scale on your finger than balancing on a match stick. While balancing the meter scale in stable equilibrium. The vertical line passes through the center of gravity of scale should pass through the base of supporting material. The finger has more base over than a match stick.
- 34. Let us consider a sphere of radius r which falls freely through a highly viscous liquid of coefficient of viscosity η. Let the density of the material of the sphere be p and the density of the fluid be c. Gravitational force acting on the sphere, F G = mg = \(\frac { 4 }{ 3 }\)πr³pg (downward force) Upthrust, U= \(\frac { 4 }{ 3 }\)πr³σg (upward force) viscous force F = 6πηrv t At terminal velocity v t. downward force = upward force.
- 35. In a collision, the total K.E of the bodies before collision is equal to the total K.E. of the bodies after collision, then it is an elastic collision. Total K.E. before collision = Total K.E. after collision Inelastic collision: In a collision, the total K.E. of the bodies before collision is not equal to total K.E. after collision then it is called as inelastic collision Even though K.E. is not conserved but total energy is conserved. After collision of the two colliding bodies stick together such collision are called as perfectly inelastic a plastic collision.
- 36. The vector product or cross product of two vectors is defined as another vector having a magnitude equal to the product of the magnitudes of two vectors and the sine of the angle between them. The direction of the product vector is perpendicular to the plane containing the two vectors, in accordance with the right hand screw rule or right hand thumb rule. Thus, if\(\overrightarrow{\mathrm{A}}\) and \(\overrightarrow{\mathrm{B}}\) are two vectors, then their vector product is written as \(\overrightarrow{\mathrm{A}}\) × \(\overrightarrow{\mathrm{B}}\) which is a vector C defined by \(\overrightarrow{\mathrm{c}}\) = \(\overrightarrow{\mathrm{A}}\) x \(\overrightarrow{\mathrm{B}}\) = (AB sin…
- 37. (1) All non zero digits are significant Example: 1342 has 4 significant figures (2) All zeros between two non-zero digits are significant Example: 2008 has four significant figures (3) All zeros to the right of non-zero digit but to the left of the decimal point are significant. Example: 3070.00 has 4 significant figures. (4) The trailing zeros are not significant, ie in the number without a decimal point. All zeros are significant if they come from the measurement. Example: 4000 has one significant figure. (5) If a number is less than 1, the zero (s) on the right of the decimal point but to the left of the first non-zero digit are not significant. Example: 0.0034 has 2 significant figure…
- 38. When porter is carrying a sack of rice, on his back, the position of center of gravity changes. In order to bring it in the middle for stable equilibrium, porter bends forward.
- 39. The frequency of external periodic force (or driving force) matches with the natural frequency of the vibrating body (driven). As a result, the oscillating body begins to vibrate such that its amplitude increases at each step and ultimately it has a large amplitude. Such a phenomenon is known as resonance and the corresponding vibrations are known as resonance vibrations. Example: The breaking of glass due to sound III. Long Answers Questions: