Physics · Science General

Units and Measurement

998 Questions

Master the fundamentals of physics with these practice questions on units and measurement. The topics include fundamental SI units, derived quantities, and specific units for power, force, and light. These questions are essential for building a strong foundation for competitive exams.

SI fundamental unitsUnits of powerDerived quantities unitsThermal energy unitsVolume measurement unitsElectric current units

Units and Measurement Questions

Multiple choice

Dyne (dyn) is a unit of force in

  1. CGS

  2. MKS

  3. FPS

  4. SI
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

1    dyne is the CGS unit of force, Definition: it is the force which accelerates a mass of one gram at the rate of one centimetre per second .

Multiple choice

The unit for magnetic flux density is

  1. erg

  2. gilbert (Gi)

  3. gauss (G)

  4. Maxwell (Mx)
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

3      the CGS unit of magnetic flux density is gauss This exerts a force of 0.1 dyne per ampere on a current-carrying conductor placed in the field.

Multiple choice

Calorie (cal) is a unit for

  1. electric energy

  2. magnetic energy

  3. heat energy

  4. all of above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

3   The CGS unit of heat energy is cal. The amount of heat required at a pressure of one atmosphere to raise the temperature of one gram of water by one degree Celsius.

Multiple choice

Newton is a unit for force in SI, 1 Newton is equal to

  1. 105 dyne

  2. 1010 dyne

  3. 10-5 dyne

  4. 10-10 dyne
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

1        The newton, is the force which accelerates a mass of one kilogram at the rate of one meter per second . The ratio between a CGS unit and the corresponding MKS unit is usually a power of 10. A newton accelerates a mass 1000 times greater than a dyne does, and it does so at a rate 100 times greater, so there are 100 000 = 105 dynes in a newton.

Multiple choice

Weber (Wb) is the SI unit for

  1. magnetic dipole

  2. magnetic flux

  3. magnetic moment

  4. electric flux
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

2   The SI unit of magnetic flux is weber . Flux is the rate (per unit of time) at which something crosses a surface perpendicular to the flow. If the something is a magnetic field, then the magnetic flux across a perpendicular surface is the product of the magnetic flux density.

Multiple choice

No. of base SI units are

  1. 8

  2. 3

  3. 7

  4. 6
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

3   There are seven base SI units (for mass, length, time, electric current, temperature, luminous intensity, and amount of substance) from which the other units may be derived.

Multiple choice

Which of the following is not a unit of radiation measursment?

  1. Roentgen

  2. Light year

  3. Radiation absorbed dose

  4. Roentgen equivalent man

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A light-year is a unit of length used by astronomers to measure interstellar distance (the distance between stars). A light-year is defined as the distance that light will travel in a year.

Multiple choice

Decibel is the unit of

  1. speed

  2. sound

  3. distance

  4. energy
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The decibel (dB) is a logarithmic unit used to express the ratio of two values of a physical quantity, most commonly sound pressure level.

Multiple choice

Unit of pressure is

  1. pascal

  2. Kpa

  3. N/m

  4. none of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The pascal (symbol: Pa) is the SI derived unit of pressure, internal pressure, stress, Young's modulus and tensile strength, named after the French mathematician, physicist, inventor, writer, and philosopher Blaise Pascal. It is a measure of force per unit area, defined as one newton per square metre.

Multiple choice

In CGS system the unit of length is

  1. metre

  2. centimetre

  3. decimetre

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In the CGS (Centimetre-Gram-Second) system, the unit of length is the centimetre.

Multiple choice

The Torque- a power to generate revolutions is expressed as (its unit is kg metre) -

  1. Length of arm (m) x Force (kg)

  2. Length of arm (cm) x Force (kg)

  3. Length of arm (m) x Force (g)

  4. Length of arm (rom) x Force (mg)
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Torque is defined as the product of the force applied and the perpendicular distance from the pivot point (the lever arm). In SI units, this is Force (Newtons) * distance (meters), but in the context of the question's units, it is Force (kg) * distance (m).

Multiple choice

Light year is the unit of

  1. Time

  2. Distance

  3. Light

  4. Intensity of light
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A light year is the distance that light travels in a vacuum in one Julian year. It is a unit of distance, not time.