Tag: units - definitions and systems

Questions Related to units - definitions and systems

The CGS unit of energy is the dye.

physics motion and measurement physical quantities units - definitions and systems physical quantities like mass and weight

  1. True

  2. False

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Correct Option: B
Explanation:

 The CGS unit of energy is erg. The erg is a unit of energy equal to $10^{-7}$ joules.

Which quantities are measured in the same unit?

physics motion and measurement physical quantities units - definitions and systems physical quantities like mass and weight

  1. energy, power and work

  2. energy and power, but not work

  3. energy and work, but not power

  4. power and work, but not energy

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Correct Option: C
Explanation:
Quantity             Dimension
Energy              $ML^2T^{-2}$
Work                  $ML^2T^{-2}$
Power                 $ML^2T^{-3}$

So, the dimension of energy and work is same but different to power.
Option (C) is correct.

Watt-hour measures

physics motion and measurement physical quantities units - definitions and systems physical quantities like mass and weight

  1. current

  2. voltage

  3. power

  4. electric energy

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Correct Option: D
Explanation:

Watt is unit of power, hour is unit of time. 

Thus Watt-hour means Power x Time, which is energy.

Maxwell is the unit of

physics motion and measurement physical quantities units - definitions and systems physical quantities like mass and weight

  1. magnetic susceptibility

  2. intensity of magnetisation

  3. magnetic flux

  4. magnetic permeability

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Correct Option: C
Explanation:

In C.G.S system, Maxwell is the unit of magnetic flux 
$1 Wb(S.I unit)=10^8\ maxwell$

Find out the odd one from the given options.

physics motion and measurement physical quantities units - definitions and systems physical quantities like mass and weight

  1. $Calorie$

  2. $Joule$

  3. $Ampere$

  4. $Kelvin$

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Correct Option: C
Explanation:

(3) Ampere
Because Calorie,Joule and Kelvin are related to Heat.
But, Ampere is the unit of current.

Read the following statements carefully and pick out the correct choice of answer.
A: Electromotive force is expressed in Newtons.
B: Electric intensity is expressed in ${ VC }^{ -1 }$.

physics motion and measurement physical quantities units - definitions and systems physical quantities like mass and weight

  1. Both A and B are correct.

  2. Both A and B are wrong.

  3. A is correct but B is wrong.

  4. A is wrong but B is correct.

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Correct Option: B
Explanation:

Electromotive force is the voltage developed by any source of electrical energy such as a battery or dynamo. It is generally defined as the electrical potential for a source in a circuit.

It is not a force but voltage and its unit is volt.

Electric intensity at a point is defined as the force experienced per unit positive charge at a point placed in the electric field. 
Its unit is $Newton/Coloumb=NC^{-1}$

Both statements are wrong.

Read the following statements carefully and pick out the correct choice of answer.
A: Susceptibility is expressed as ${ Am }^{ -1 }$.
B: Magnetic flux is expressed ${ JA }^{ -1 }$.

physics motion and measurement physical quantities units - definitions and systems physical quantities like mass and weight

  1. A is correct but B is wrong.

  2. A is wrong but B is correct.

  3. Both A and B are wrong.

  4. Both A and B are correct.

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Correct Option: B
Explanation:

Susceptibility is unit less.
Magnetic flux is expressed $Vs$ or $[M^1L^2T^{-2}A^{-1}] = JA^{-1}$.


Hence, option B is correct.

India adopted metric system of units in

physics motion and measurement physical quantities units - definitions and systems physical quantities like mass and weight

  1. 1947

  2. 1950

  3. 1956

  4. 2000

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Correct Option: C
Explanation:

The metric system in weights and measures was adopted by the Indian Parliament in December 1956 with the Standards of Weights and Measures Act, which took effect beginning 1 October 1958. 

Henry is the unit of

physics motion and measurement physical quantities units - definitions and systems physical quantities like mass and weight

  1. self inductance (or) mutual inductance

  2. e.m.f

  3. capacity

  4. conductivity

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Correct Option: A
Explanation:

Henry is the unit of Inductance.
Volt is the unit of emf.
Farad is the unit of capacity.
$(\dfrac{1}{\rho})$ is the unit of conductivity.

SI units were introduced in

physics motion and measurement physical quantities units - definitions and systems physical quantities like mass and weight

  1. 1960

  2. 1956

  3. 1947

  4. None of these

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Correct Option: A
Explanation:

The International System of Units, universally abbreviated S.I. is the modern metric system of measurement. The S.I. was established in 1960 by the 11th General Conference on Weights and Measures.