- A. CGS
- B. MKS
- C. FPS
- D. SI
(c) FPS
- A. Base
- B. Supplementary
- C. Derived
- D. professional
(a) Base
- A. Celsius
- B. Fahrenheit
- C. kelvin
- D. Ampere
(c) kelvin
- A. Directly proportional to the number of atoms
- B. Inversely proportional to the number of atoms
- C. Directly proportional to the square of number of atoms
- D. Inversely proportional to the square of number of atoms
(a) directly proportional to the number of atoms
- A. Laser light
- B. UV light
- C. Visible light
- D. IR light
(c) visible light
- A. International system of units
- B. Integrated System of units
- C. International symbol of units
- D. Integrated symbol of units
(a) International system of units
- A. Accuracy
- B. Precision
- C. Error
- D. Approximation
(b) Precision
- A. Supplementary quantities
- B. Derived quantities
- C. Professional quantities
- D. Energy quantities
(b) Derived quantities
- A. Approximation gives accurate value.
- B. Approximation simplifies the calculation.
- C. Approximation is very useful when little information is available.
- D. Approximation gives the nearest value only.
(a) Approximation gives accurate value.
Steradian
Scientists
Temperature
Ammeter
One mole
Solid angle
Electronic
Error
Accuracy
plane angle
False. The correct statement is: Temperature is a measure of the average kinetic energy of the particles in a system. While the total kinetic energy depends on the total number of particles and their individual speeds, temperature specifically reflects the average kinetic energy per particle, which determines how fast the particles are moving on average.
False. The correct statement is: One coulomb of charge flowing per second is called an ampere. An ampere is the SI unit of electric current, defined as the flow of one coulomb of electric charge in one second. This is a fundamental unit in the International System of Units used to measure the rate of flow of electric charge through a conductor.
True. The amount of substance is a fundamental physical quantity that gives the number of particles (atoms, molecules, ions, or other elementary entities) present in a substance. It is measured in moles, where one mole contains Avogadro's number of particles, approximately 6.022 × 10²³. This quantity is essential in chemistry and physics for relating macroscopic properties of matter to the microscopic number of particles.
True. The intensity of light from a candle is approximately equal to one candela. The candela is the SI unit of luminous intensity, which measures the brightness of light emitted in a particular direction. Historically, the candela was defined based on the light produced by a standard candle, and a typical candle produces a luminous intensity of approximately one candela.
True. The angle formed at the top of a cone is an example of a plane angle. A plane angle is an angle formed by two rays or lines meeting at a point in a plane. The angle at the apex of a cone, measured between two lines extending from the tip to the base, is a two-dimensional angle and therefore qualifies as a plane angle.
False. The correct statement is: Atomic clocks are used in GPS devices. Atomic clocks are extremely precise timekeeping instruments that use the oscillations of atoms to measure time with exceptional accuracy. GPS systems rely on atomic clocks to calculate precise positions and timing information, as even tiny errors in time measurement would result in significant errors in location determination.
True. The number 4.582 can be rounded off as 4.58. When rounding to two decimal places, we look at the third decimal digit, which is 2. Since 2 is less than 5, we round down, keeping the second decimal place as 8. Therefore, 4.582 rounded to two decimal places is 4.58.
(b) Both assertion and reason are true but reason is not the correct explanation of the assertion
Correct explanation :
In SI system the units are precisely defined and have the same value everywhere.
(a) Both assertion and reason are true and reason is the correct explanation of the assertion
(d) Assertion is false, but reason is true]
Correct explanation :
Radian is the unit of plane angle.
Seven.
The instrument used for the measurement of temperature is a thermometer. A thermometer is a device that contains a liquid (such as mercury or alcohol) or uses electronic sensors to measure the degree of hotness or coldness of a substance or environment. Thermometers work on the principle that liquids or materials expand or contract with changes in temperature, allowing us to read the temperature value on a calibrated scale.
The lower fixed point of the Fahrenheit scale is 32°F. This is the temperature at which water freezes under standard atmospheric pressure. The Fahrenheit scale was established with two fixed points: the lower fixed point at 32°F (freezing point of water) and the upper fixed point at 212°F (boiling point of water), with 180 equal divisions between them.
The SI unit of luminous intensity is candela, abbreviated as cd. Candela is one of the seven fundamental SI units and is used to measure the intensity of light emitted by a source in a particular direction. It is defined based on the light produced by a standard source and is essential for measuring the brightness of light sources in various applications.
The type of oscillations used in atomic clocks are periodic vibrations of atoms, specifically the oscillations of electrons in atoms. Atomic clocks use the natural frequency of oscillation of atoms such as cesium or rubidium. These oscillations are extremely regular and consistent, making atomic clocks the most accurate timekeeping devices available, with precision far exceeding that of mechanical or quartz clocks.
Based on their display, clocks are of two types: analog clocks and digital clocks. Analog clocks display time using moving hands (hour hand, minute hand, and sometimes a second hand) that point to numbers on a circular dial. Digital clocks display time as numerical digits on a screen or display panel, showing hours and minutes in a numerical format, and sometimes seconds as well.
One time.
60 minutes = 1 hr
1 minute = \(\frac { 1 }{ 60 }\) = 0.0167 hours.
There are several common systems of measurement used to express physical quantities. The FPS system uses Foot for length, Pound for mass, and Second for time. The CGS system uses Centimetre for length, Gram for mass, and Second for time. The MKS system uses Metre for length, Kilogram for mass, and Second for time. Among these, the MKS system forms the basis of the International System of Units (SI), which is the most widely used system in science and engineering today. Each system has its own advantages and is used in different contexts depending on the region and field of application. The SI system, derived from MKS, is the standard system adopted internationally for scientific measurements and calculations.
One ampere is defined as one coulomb of charge moving in a conductor in one second. In other words, if a charge of one coulomb passes through a cross-section of a conductor in one second, the electric current flowing through that conductor is said to be one ampere. Ampere is the SI unit of electric current and is named after the French physicist André-Marie Ampère. It is one of the seven base units in the International System of Units.
Electric current is the flow of electric charge through a conductor. The magnitude of an electric current is the amount of electric charges flowing through a conductor in one second. It is measured in amperes, where one ampere represents the flow of one coulomb of charge per second. Electric current can flow through various materials such as metals, liquids, and gases, and it is the basis for all electrical phenomena and applications.
Luminous intensity is the measure of the power of the emitted light by a light source in a particular direction, per unit solid angle. It describes how bright a light source appears in a specific direction and is measured in candelas in the SI system. Luminous intensity is different from total luminous flux, as it focuses on the brightness in a particular direction rather than the total light emitted in all directions. This property is important in applications such as lighting design, where the directional brightness of a source matters significantly.
Mole is defined as the amount of substance which contains 6.023 × 10²³ entities, such as atoms, molecules, ions, or electrons. This number is known as Avogadro's number, named after the Italian scientist Amedeo Avogadro. The mole is the SI base unit for the amount of substance and is used in chemistry to relate the microscopic world of atoms and molecules to the macroscopic quantities that we can measure in the laboratory. For example, one mole of carbon-12 has a mass of exactly 12 grams.
Plane angle and solid angle are two different types of angles used in geometry and physics. A plane angle is formed by the intersection of two lines or two planes and is two-dimensional in nature. The unit of plane angle is the radian. A solid angle, on the other hand, is formed by the intersection of three or more planes at a common point and is three-dimensional in nature. The unit of solid angle is the steradian. Plane angles are commonly used in two-dimensional geometry and trigonometry, while solid angles are used in three-dimensional geometry, optics, and radiation studies. For example, the angle between two sides of a triangle is a plane angle, whereas the angle subtended by a cone at its apex is a solid angle.
The seven base quantities and their corresponding SI units are as follows: length is measured in metres, mass in kilograms, time in seconds, electric current in amperes, temperature in kelvin, amount of substance in moles, and luminous intensity in candelas. These base quantities are fundamental and independent of each other, and all other physical quantities can be derived from combinations of these base quantities and their units. For example, velocity is derived from length and time, force is derived from mass, length, and time, and energy is derived from mass, length, and time.
Types of clocks based on display:
Analog clocks
Digital clocks
1. Analog clocks:
It looks like a classic clock. It has three hands to show the time.
Hours Hand : It is short and thick. It shows ‘hour’.
Minutes Hand : It is long and thin. It shows ‘minute’.
Seconds Hand : It is long and very thin. It shows ‘second’. It makes one rotation in one minute and 60 rotations in one hour.
Analog clocks can be driven either mechanically or electronically.2. Digital clocks:
A digital clock displays the time directly. It shows the time in numerals or other
symbols. It may have a 12 hours or 24 hours display.
Recent clocks are showing Date, Day, Month, Year, Temperature etc.
Digital clocks are often called as Electronic Clocks.
Différent types of clocks based on working mechanism:
1. Quartz Clock:
These clocks are activated by ‘electronic oscillations’, which are controlled by a ‘quartz crystal’.
The frequency of a vibrating crystal is very precise. So, the quartz clock is more accurate than the mechanical clock.
These clocks have an accuracy of one second in every 10 9 seconds.2. Atomic Clock:
These clocks are making use of periodic vibrations occurring within the atom.
These clocks have an accuracy of one second in every 10b seconds.
Atomic clocks are used in Global Positioning System (GPS), Global Navigation Satellite System (GLONASS) and International time distribution services.
No, it is not possible to have a fever of 100°C. This statement contains a significant error in the temperature scale used. The normal body temperature of a healthy human being is approximately 98.4°F to 98.6°F, which is equivalent to about 37°C. A temperature of 100°C is the boiling point of water at standard atmospheric pressure, and no living human can survive such a high body temperature. Your friend should have said that he had a fever of 100°F, which is approximately 37.8°C and represents a mild to moderate fever. The confusion likely arose from mixing up the Fahrenheit and Celsius temperature scales. When discussing body temperature and fever, it is important to specify the correct scale, as 100°C would be fatal, whereas 100°F is a treatable fever that requires medical attention.