Ch 1Nature of Physical World and Measurement
5-Mark Questions
Briefly explain the types of physical quantities?
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.
How will you measure the diameter of the moon using the parallax method?
In order to determine the diameter of the moon, initially, a distance of the moon is calculated using the parallax method. Let D be the distance of the moon from the earth. Let d be the diameter of the moon. Let ∝ be the angular size of the angular diameter of the moon (ie) the angle subtended by d at the earth. We have ∝ = d/D d = ∝ D The angle ∝ can be measured from the same location on the earth. When two diametrically opposite points of the moon are viewed through a telescope, the angle between the two directions gives the angular size or angular diameter. …
2-Mark Questions
What is the difference between mN, Nm, and nm?
mN means milli newton, 1 mN = 10 -3 N, Nm means Newton meter, nm means nanometer.
Assuming that the frequency γ of the vibrating string may depend up on (i) applied force (F) (ii) Length (l) (iii) mass per unit length (m) prove that γ ∝ \(\frac { 1 }{ l }\)\(\sqrt{\frac{F}{m}}\) using dimensional analysis.
γ ∝ F a l b m c Writing dimension on both sides Hence Proved.
1-Mark Questions (MCQ)
One of the combinations from the fundamental physical constants is \(\frac { hG }{ G }\), The unit of this expression is. (a) Kg² (b) m³ (c) S -1 (d) m
(a) Kg²
Ch 2Kinematics
5-Mark Questions
What are the different types of motion? State one example for each & explain.
The different types of motions are: a) Linear motion: An object is said to be in linear motion if it moves in a straight line. Example: An athlete running on a straight tack. b) Circular motion: It is defined as a motion described by an object traveling a circular path. Example: The motion of a satellite around the earth C) Rotational motion: If any object moves in a rotational motion about an axis the motion is rotational motion. During rotation, every point in the object traverses a circular path about an axis. …
How will you differentiate motion in one dimension, two dimensions, and in three dimensions?
Motion in one dimension: One-dimensional motion is the motion of a particle moving along a straight line. Example: An object falling freely under gravity close to the earth. Motion in two dimensions: If a particle is moving along a curved path in-plane, then it is said to be in two-dimensional motion. Example: Motion of a coin in a carom board. Motion in three dimensions: A particle moving in usual three-dimensional space has three-dimensional motion. Example: A bird flying in the sky.
2-Mark Questions
Can a body have a constant speed and still have varying velocity?
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.
Can two non-zero vectors give zero resultant when they multiply with each other?
If yes condition for the same. Yes. for example, the cross product of two non-zero vectors will be zero when θ = 0 or θ = 180°.
Define a vector. Give Example.
Vector is a quantity which is described by both magnitude and direction. Geometrically a vector is a directed line segment. Example – force, velocity, displacement.
1-Mark Questions (MCQ)
The branch of mechanics which deals with the motion of objects without taking force into account is –
(c) kinematics
Ch 3Laws of Motion
5-Mark Questions
A vehicle is moving along the positive x-direction, if a sudden brake is applied, then _______. a) frictional force acting on the vehicle is along negative x-direction b) frictional force acting on the vehicle is along the positive x-direction c) no frictional force acts on the vehicle d) frictional force acts in a downward direction
a) frictional force acting on the vehicle is along the negative x-direction Normal force formula is the support force exerted upon an object that is in contact with another stable object.
Explain the concept of Inertia. Write two examples each for Inertia of motion, inertia of rest and inertia of direction.
The inability of objects to move on its own or change its state of motion is called inertia. Inertia means resistance to change its state. There are three types of inertia: 1. Inertia of rest: The inability of an object to change its state of rest is called inertia of rest. Example: * When a stationary bus starts to move, the passengers experience a sudden backward push. * A book lying on the table will remain at rest until it is moved by some external agencies. 2. …
2-Mark Questions
A book is at rest on the table which exerts a normal force on the book. If this force is considered as a reaction force, what is the action force according to Newton’s third law? a) Gravitational force exerted by Earth on the book b) Gravitational force exerted by the book on Earth c) Normal force exerted by the book on the table d) None of the above
c) Normal force exerted by the book on the table
Define one newton:
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.
State Newton’s third law.
Newton’s third law states that for every action there is an equal and opposite reaction.
1-Mark Questions (MCQ)
When an object of mass m slides on a frictionless surface inclined at an angle θ, then the normal force exerted by the surface is-
(b) mg cos θ
Ch 4Work, Energy and Power
5-Mark Questions
Explain how the definition of work in physics is different from general perception.
The term work is used in diverse contexts in daily life. It refers to both physical as well as mental work. In fact, any activity can generally be called work. But in Physics, the term work is treated as a physical quantity with a precise definition. Work is said to be done by the force when the force applied to a body displaces it.
Write the various types of potential energy. Explain the formulate.
The energy possessed by the body by virtue of its position is called potential energy. The various types of potential energies are 1) Gravitational potential energy: The energy possessed by the body due gravitational force gives gravitational potential energy u = mgh. where u → Gravitational potential energy m → Mass of the body g → acceleration due to gravity h → displacement produced 2) Elastic potential energy: The energy due to spring force and other similar forces give rise to elastic potential energy u = 1/2² Where U → elastic potential energy K → spring constant x → elongation produced …
2-Mark Questions
A ball of mass 1 kg and another of mass 2 kg are dropped from a tall building whose height is 80 m. After, a fall of 40 m each towards Earth, their respective kinetic energies will be in the ratio of _______. (AIPMT model 2004) a) \(\sqrt{2}\): 1 b) 1: \(\sqrt{2}\) c) 2: 1 d) 1: 2
d) 1: 2 This online Velocity Calculator is used to find the velocity of water in a pipe with the flow rate and diameter of the pipe.
An engine pumps water continuously through a hose. Water leaves the hose with a velocity v and m is the mass per unit length of the water of the jet. What is the rate at which kinetic energy is imparted to water? (AIPMT 2009) a) \(\frac { 1 }{ 2 }\) mv 3 b) mv 3 c) \(\frac { 3 }{ 2 }\)mv² d) \(\frac { 5 }{ 2 }\) mv²
a) \(\frac { 1 }{ 2 }\) mv 3
Two different unknown masses A and B collide. A is initially at rest when B has a speed V. After collision B has a speed V/2 and moves at right angles to its original direction of motion. Find the direction in which A moves after collision.
Applying principle of conservation of momentum along x-axis Applying principle of conservation of momentum along y-axis
1-Mark Questions (MCQ)
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
c) 10 J
Ch 5Motion of System of Particles and Rigid Bodies
5-Mark Questions
Define torque and mention its unit.
Torque is defined as the moment of the external applied force about a point or axis of rotation. The expression for torque is, \(\vec{\tau}\) = \(\vec{r}\) x \(\vec{F}\)
What are the conditions in which force cannot produce torque?
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
2-Mark Questions
The motion of center of mass of a system of two particles is unaffected by their internal forces- (a) irrespective of the actual directions of the internal forces (b) only if they are along the line joining the particles (c) only if acts perpendicular to each other (d) only if the acting opposite
(a) irrespective of the actual directions of the internal forces
Define center of mass.
The center of mass of a body is defined as a point where the entire mass of the body appears to be concentrated.
Find out the center of mass for the given geometrical structures.
b) Cylinder: The center of mass in case of the cylinder lies on the vertical axis and at the centre of the cylinder.
1-Mark Questions (MCQ)
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
d) force acting on particle
Ch 6Gravitation
5-Mark Questions
State Kepler’s three laws.
Law of Orbits: Each planet revolves moves around the Sun in an elliptical orbit with the Sun at one of the foci of the ellipse. Law of area: The radial vector line joining the Sun to a planet sweeps equal areas in equal intervals of time. Law of period: The square of the time period of revolution of a planet around the Sun in its elliptical orbit is directly proportional to the cube of the semi-major axis of the ellipse.
Will the angular momentum of a planet be conserved? Justify your answer.
The torque experienced by the Earth due to the gravitational force of the Sun is given by, It implies that angular momentum \(\vec { L }\) is constant vector. Hence L is conserved.
2-Mark Questions
A planet moving along an elliptical orbit is closest to the Sun at distance r 1 and farthest away at a distance of r 2. If v 1 and v 2 are linear speeds at these points respectively. Then the ratio \(\frac{v_{1}}{v_{2}}\) is: (NEET 2016) (a) \(\frac{r_{2}}{r_{1}}\) (b) (\(\frac{r_{2}}{r_{1}}\))² (c) \(\frac{r_{1}}{r_{2}}\) (d) (\(\frac{r_{1}}{r_{2}}\))²
(a) \(\frac{r_{2}}{r_{1}}\) Hint: v = rw ∴ v ∝ r \(\frac{v_{1}}{v_{2}}\) = \(\frac{r_{1}}{r_{2}}\)
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
(b) 2 times of original value masses and inversely proportional to square
State Newton’s Universal law of gravitation.
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.
1-Mark Questions (MCQ)
The linear momentum and position vector of the planet is perpendicular to each other at:
(a) perihelion and aphelion Hint: At aphelion Potential Energy is more and Kinetic energy is less. At perihelion Potential Energy is less and Kinetic Energy is more.
Ch 7Properties of Matter
5-Mark Questions
Define stress and strain.
Stress: The force per unit area is called as stress. Stress, σ = \(\frac { Force }{ Area }\) = \(\frac { F }{ A }\) Strain: Strain is defined as the ratio of change in size to the original size of an object. It measures the degree of deformation.
Explain elasticity using intermolecular forces.
Elastic behaviour of solid. In a solid, atoms and molecules are arranged in such a way that each molecule is acted upon by the forces due to the neighbouring molecules. When deforming force is applied on a body so that its length increases, then the molecules of the body go far apart.
2-Mark Questions
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
(c) energy = 3VT (\(\frac { 1 }{ r }\) – \(\frac { 1 }{ R }\))is released
State Hooke’s law of elasticity.
It states that for small deformation, the stress is directly proportional to strain.
Define Poisson’s ratio.
It is defined as the ratio of relative contraction (lateral strain), to relative expansion (longitudinal strain).
1-Mark Questions (MCQ)
Consider two wires X and Y. The radius of wire X is 3 times the radius of Y. If they are stretched by the same load then the stress on Y is:
(c) nine times that on X Hint:
Ch 8Heat and Thermodynamics
5-Mark Questions
‘An object contains more heat’- is it a right statement? If not why?
When heated, an object receives heat from the agency. Now object has more internal energy than before. Heat is the energy in transit and which flows from an object at a higher temperature to an object at lower temperature. Heat is not a quantity. So the statement I would prefer “an object contains more thermal energy”.
Obtain an ideal gas law from Boyle’s and Charles’law.
According to Boyle’s law, Pressure ∝ \(\frac { 1 }{ 2 }\) i.e., P ∝ \(\frac { 1 }{ V }\) According to Charle’s law, Volume ∝ Temperature, i.e., V ∝ T By combining these two laws, we get PV= CT … (1) Where C is a positive constant But C = k x Number of particles (N) C = kN Where k – Boltzmann’s constant. ∴ Equation (1) becomes PV = NkT
2-Mark Questions
Define one mole.
One mole of any substance is the amount of that substance which contains Avogadro number (NA) of particles (such as atoms or molecules).
Define molar specific heat capacity.
Heat energy required to increase the temperature of one mole of substance by IK or 1°C.
What is a thermal expansion?
Thermal expansion is the tendency of matter to change in shape, area, and volume due to a change in temperature.
1-Mark Questions (MCQ)
In hot summer after a bath, the body’s:
(a) internal energy decreases
Ch 9Kinetic Theory of Gases
5-Mark Questions
For a given gas molecule at a fixed temperature, the area under the Maxwell- Boltzmann distribution curve is equal to: (a) \(\frac { PV }{ kT }\) (b) \(\frac { kT }{ PV }\) (c) \(\frac { P }{ NkT }\) (d) PV
(a) \(\frac { PV }{ kT }\) Hint: The area under the graph will give total number of gas molecules in the system. n = \(\frac { PV }{ RT }\) R = k n = \(\frac { PV }{ kT }\)
What is the microscopic origin of pressure? kinetic energy and pressure?
The microscopic origin of pressure was proposed by considering a thermodynamic system as a collection of molecules. By the kinetic theory of gases, the pressure is linked to the velocity of molecules (v) and number density (\(\frac {N}{ V }\)) p = \(\frac { 1 }{ 3 }\)\(\frac { N }{ V }\)mv² Where v – velocity of molecular \(\frac { N }{ V }\) – number density
2-Mark Questions
What is the relation between the average kinetic energy and pressure?
P = \(\frac {2}{ 3 }\)\(\overline{KE}\)
Define mean free path and write down its expression.
Average distance travelled by the molecule between collisions is called mean free path (λ). λ = \(\frac{1}{\sqrt{2} n \pi d^{2}}\)
If the rms speed of methane gas in Jupiter’s atmosphere is 471.8 ms -1, shows that the surface temperature of Jupiter is sub-zero.
Let the temperature of Jupiter be T. The temperature of Jupiter is = -130°C
1-Mark Questions (MCQ)
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 Hint: As it moves with respect to X axis ∆p x = – mu ∆p y = 0
Ch 10Oscillations
5-Mark Questions
A spring is connected to a mass m Suspended from it and its time period for vertical oscillation is T. The spring is now cut into two equal halves and the same mass is suspended from one of the halves. The period of vertical oscillation is: (a) T’ = \(\sqrt{2}\)T (b) T’ = \(\frac{\mathrm{T}}{\sqrt{2}}\) (c) T’ = \(\sqrt{2T}\) (d) T’ = \(\sqrt{\frac{\mathrm{T}}{2}}\)
(b) T’ = \(\frac{\mathrm{T}}{\sqrt{2}}\) Hint: T = 2π\(\sqrt{\frac{\mathrm{m}}{k}}\) When the spring is cut into two equal halves, then the force constant of each part is 2k. When the mass is suspended from one of the halves. Time period T’ = 2π\(\sqrt{\frac{\mathrm{m}}{2k}}\) = \(\sqrt{\frac{\mathrm{T}}{2}}\)
What is meant by periodic and non-periodic motion? Give any two examples, for each motion.
Periodic motion: Any motion which repeats itself in a fixed time interval is known as periodic motion. Examples: Hands in a pendulum clock, the swing of a cradle. Non-Periodic motion: Any motion which does not repeat itself after a regular interval of time is known as non-periodic motion. Example: Occurrence of Earthquake, the eruption of a volcano.
2-Mark Questions
A simple pendulum is suspended from the roof of a school bus which moves in a horizontal direction with an acceleration a, then the time period is: (a) T ∝ \(\frac{1}{g^{2}+a^{2}}\) (b) T ∝ \(\frac{1}{\sqrt{g^{2}+a^{2}}}\) (c) T ∝ \(\sqrt{g^{2}+a^{2}}\) (d) T ∝ (g² + a²)
(b) T ∝ \(\frac{1}{\sqrt{g^{2}+a^{2}}}\) Hint: T = 2π\(\sqrt{\frac{l}{g}}\) When a bus is moving g’ = \(\sqrt{g^{2}+a^{2}}\) ∴ T ∝ \(\frac{1}{\sqrt{g^{2}+a^{2}}}\)
Two bodies A and B whose masses are in the rati0 1:2 are suspended from two separate massless springs of force constants k A and k B respectively. If the two bodies oscillate vertically such that their maximum velocities are in the ratio 1:2, the ratio of the amplitude A to that of B is: (a) \(\sqrt{\frac{k_{\mathrm{B}}}{2 k_{\mathrm{A}}}}\) (b) \(\sqrt{\frac{k_{\mathrm{B}}}{8 k_{\mathrm{A}}}}\) (c) \(\sqrt{\frac{2k_{\mathrm{B}}}{ k_{\mathrm{A}}}}\) (d) \(\sqrt{\frac{8k_{\mathrm{B}}}{ k_{\mathrm{A}}}}\)
(b) \(\sqrt{\frac{k_{\mathrm{B}}}{8 k_{\mathrm{A}}}}\) Hint: v A: v B Amplitude of A: Amplitude of B = \(\sqrt{\mathrm{K}_{\mathrm{B}}}: \sqrt{8 \mathrm{~K}_{\mathrm{A}}}\)
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\(\sqrt{m\left(k_{1}+k_{2}\right)}\)
(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.
1-Mark Questions (MCQ)
In a simple harmonic oscillation, the acceptation against displacement for one complete oscillation will be: (Model NSEP 2000 – 01)
(d) a straight line Hint: The sketch between cause (magnitude of acceleration) and effect (magnitude of displacement) is a straight line.
Ch 11Waves
5-Mark Questions
A person standing between two parallel hills fires a gun and hears the first echo after t 1 sec and the second echo after t 2 sec. The distance between the two hills is: (a) \(\frac{v\left(t_{1}-t_{2}\right)}{2}\) (b) \(\frac{v\left(t_{1} t_{2}\right)}{2\left(t_{1}+t_{2}\right)}\) (c) v(t 1 + t 2 ) (d) \(\frac{v\left(t_{1}+t_{2}\right)}{2}\)
(d) \(\frac{v\left(t_{1}+t_{2}\right)}{2}\) Hint: For first echo 2d 1 = vt 1 For second echo 2d 2 = vt 2 ∴ d = d 1 + d 2 = \(\frac{v\left(t_{1}+t_{2}\right)}{2}\)
An organ pipe A closed at one end is allowed to vibrate in its first harmonic and another pipe B open at both ends is allowed to vibrate in its third harmonic. Both A and B are in resonance with a given tuning fork. The ratio of the length of A and B is: (a) \(\frac { 8 }{ 3 }\) (b) \(\frac { 3 }{ 8 }\) (c) \(\frac { 1 }{ 6 }\) (d) \(\frac { 1 }{ 2 }\)
(d) \(\frac { 1 }{ 2 }\) Hint: First harmonic of a closed organ pipe L C = \(\frac { 3 λ }{ 4 }\) Third harmonic of an open organ pipe L 0 = \(\frac { 3 λ }{ 2 }\) \(\frac{\mathrm{L}_{\mathrm{C}}}{\mathrm{L}_{\mathrm{O}}}\) = \(\frac { 3 π }{ 4 }\) x \(\frac { 3 }{ 3λ }\) = \(\frac { 2 }{ 4 }\) = \(\frac { 1 }{ 2 }\) ∴ \(\frac{\mathrm{L}_{\mathrm{C}}}{\mathrm{L}_{\mathrm{O}}}\) = \(\frac { 1 }{ 2 }\) II. Short Answer Questions:
2-Mark Questions
Write down the types of waves.
Waves can be classified into two types – * Transverse waves * Longitudinal waves
What are longitudinal waves? Give one example.
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.
Write down the relation between frequency, wavelength and velocity of a wave.
Velocity of the wave is v = λf.
1-Mark Questions (MCQ)
A student tunes his guitar by striking a 120 Hertz with a tuning fork, and simultaneously plays the 4 th string on his guitar. By keen observation, he hears the amplitude of the combined sound oscillating thrice per second. Which of the following frequencies is the most likely the frequency of the 4th string on his guitar?
(b) 117 Hint: Frequency of the fourth string can be derived from harmonic series generated by the strings. Frequencies of first 4 strings are 120, 119, 118, 117 Hz. f 4 = 117Hz
Frequently asked questions
- Briefly explain the types of physical quantities?
- 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.
- How will you measure the diameter of the moon using the parallax method?
- In order to determine the diameter of the moon, initially, a distance of the moon is calculated using the parallax method. Let D be the distance of the moon from the earth. Let d be the diameter of the moon. Let ∝ be the angular size of the angular diameter of the moon (ie) the angle subtended by d at the earth. We have ∝ = d/D d = ∝ D The angle ∝ can be measured from the same location on the earth. When two diametrically opposite points of the moon are viewed through a telescope, the angle between the two directions gives the angular size or angular diameter. …
- What is the difference between mN, Nm, and nm?
- mN means milli newton, 1 mN = 10 -3 N, Nm means Newton meter, nm means nanometer.
- Assuming that the frequency γ of the vibrating string may depend up on (i) applied force (F) (ii) Length (l) (iii) mass per unit length (m) prove that γ ∝ \(\frac { 1 }{ l }\)\(\sqrt{\frac{F}{m}}\) using dimensional analysis.
- γ ∝ F a l b m c Writing dimension on both sides Hence Proved.
These important questions are selected from the Samacheer Kalvi Class 11 Physics textbook book-back exercises to help you revise the most useful questions. Mark weightage (5/2/1) follows the usual exam pattern and may vary by exam — always check your latest syllabus and question pattern. Open each chapter for the complete set of questions and answers.