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

Light year is a unit of measurement of

  1. speed of light

  2. stellar distances

  3. speed of rockets

  4. speed of aeroplanes
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A light year is the distance light travels in one vacuum year (approximately 9.46 trillion km). It measures stellar and interstellar distances, NOT the speed of light (which is constant at about 300,000 km/s). It is not used for measuring speeds of rockets or airplanes.

Multiple choice

In SI system the unit of temperature is

  1. kelvin

  2. degree centrigrade

  3. degree fahrenheit

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

The SI (International System of Units) base unit for temperature is kelvin (K). While Celsius and Fahrenheit are commonly used in daily life, kelvin is the scientific standard, particularly in thermodynamics, where absolute temperature is measured from absolute zero.

Multiple choice

SI unit of mass is

  1. pound

  2. gram

  3. kilogram

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

The kilogram (kg) is the SI base unit of mass. Gram is a metric unit but not the base SI unit. Pound is imperial, and quintal is a non-SI metric unit. The kilogram is defined by the international prototype kilogram standard.

Multiple choice

Consider the following statements:

  1. The sievert (symbol: Sv) is an International System of Units (SI) derived unit of equivalent radiation dose.
  2. Dissolved oxygen (Oxygen saturation), as a water quality parameter is expressed in mg/l.

Which of the above statements is/are correct?

  1. Only 1

  2. Only 2

  3. Both 1 and 2

  4. Neither 1 nor 2
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
  1. The sievert (symbol: Sv) is the International System of Units (SI) derived unit of equivalent radiation dose, effective dose and committed dose. Quantities that are measured in sieverts are designed to represent the stochastic biological effects of ionizing radiation. The gray and sievert units are both special names for the SI derived units of joules per kilogram (m2/s2 if expressed in base units), though they are not interchangeable. 1. Sv = 1 J/kg = 1 Gy
    1. Dissolved Oxygen (Oxygen saturation): It is a relative measure of the amount of oxygen dissolved in water. Super saturation (excess of oxygen) can be harmful to organisms and also cause decompression sickness. It is expressed in mg/l.
Multiple choice

Directions: Choose the appropriate answer from the options given below:

Which is the unit used to measure electro motive force?

  1. Ohm

  2. Volt

  3. Ampere

  4. Knot

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

The volt (V) is the SI unit of electromotive force (emf), also known as voltage or electric potential difference. One volt is defined as the potential difference across a conductor when one ampere of current dissipates one watt of power. The unit is named after Alessandro Volta, the inventor of the electric battery. Ohm measures resistance, ampere measures current, and knot measures speed.

Multiple choice

Determines whether the system of measurement will be ________.

  1. U.K

  2. U.S.

  3. U.P.

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

Windows regional settings allow users to specify whether the measurement system will be U.S. (imperial units like inches, pounds, gallons) or metric (meters, kilograms, liters). The U.S. option uses the imperial system customary in the United States. U.K. and U.P. are not standard options in Windows measurement system settings.

Multiple choice

The unit of the intensity of sound is

  1. dyne

  2. joule

  3. knot

  4. decibel
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The decibel (dB) is the unit used to measure the intensity of sound. It quantifies sound pressure level on a logarithmic scale. Dyne is a unit of force, joule is a unit of energy/work, and knot is a unit of speed used in navigation and aviation.

Multiple choice

What is the unit of density?

  1. Kilogram per metre cube

  2. Gram per metre cube

  3. Centimetre per kilogram cube

  4. Metre per kilogram square

  5. NA
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Correct 

Multiple choice

The SI unit for force is -

  1. Torr

  2. Newton

  3. Joule

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

The SI unit of force is Newton (N). Joule is the SI unit of energy/work, Dyne is the CGS unit of force, and Torr is a unit of pressure.

Multiple choice

Torr is a unit of

  1. temperature

  2. pressure

  3. volume

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

Torr is a unit of pressure.

Multiple choice

In which unit will electric charge be measured?

  1. Volt

  2. Ohm

  3. Coulomb

  4. Joule

  5. Watt
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The coulomb (symbol: C) is the SI derived unit of electric charge (symbol: Q or q). It is defined as the charge transported by a steady current of one ampere in one second.