Tag: summary of si units

Questions Related to summary of si units

Illuminance of a surface is measured in

physics measurements and units summary of si units fundamental quantities system of units

  1. lumen

  2. candela

  3. lux

  4. lux $m^{-2}$

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Correct Option: C
Explanation:

Illuminance is luminous flux per unit area, it is measure in 'lux'.

Dyne-sec is the unit of

physics measurements and units summary of si units fundamental quantities system of units

  1. momentum

  2. force

  3. work

  4. angular momentum

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Correct Option: A
Explanation:

Change in momentum $=Force \times time=dyne-sec$

The fundamental unit is

physics measurements and units summary of si units fundamental quantities system of units

  1. newton.

  2. pascal.

  3. hertz.

  4. second.

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Correct Option: D
Explanation:

'Second' is a fundamental unit.

The unit of atmospheric pressure is :

physics measurements and units summary of si units fundamental quantities system of units

  1. $metre$

  2. $kg-wt$

  3. $gm { cm }^{ -2 }$

  4. $bar$

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Correct Option: D
Explanation:

Atmospheric pressure is measured in bar.

The unit of Luminous intensity is:

physics measurements and units summary of si units fundamental quantities system of units

  1. Candela

  2. Watt

  3. Lumen

  4. Ampere

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Correct Option: A
Explanation:

Candela is the unit of Luminous intensity.
Watt is the unit of power.
Lumen is the unit of luminous flux.
Ampere is the unit of current.

Siemen is the S.I unit of:

physics measurements and units summary of si units fundamental quantities system of units

  1. Electrical conductance

  2. Electrical conductivity

  3. Potential difference

  4. Inductance

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Correct Option: A
Explanation:

Siemen is the unit of Electrical conductance.
Siemens/meter is the unit of Electrical conductivity.
Voltage is the unit of Potential difference.
Henry is the unit of Inductance.

Consider the following two statements A and B and identify the correct answer.
A) The size ($u$) of the unit of physical quantity and its numerical magnitude ($n$) are related to each other by the relation nu $=$ constant
B) The choice of mass, length and time as fundamental quantities is not unique.

physics measurements and units summary of si units fundamental quantities system of units

  1. A is true but B is false

  2. B is true but A is false

  3. Both A and B are true

  4. Both A and B are false

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Correct Option: C
Explanation:

A: eg. $10$ seconds, where $n=10, u=$seconds. This is constant.
B: We can choose any quantity as fundamental and derive other quantities with respect to that

Which of the following is / are not unit(s) of time ?
a) Parsec                   b) Light-year 

c) Micron                  d) Second

physics measurements and units summary of si units fundamental quantities system of units

  1. a and c

  2. a and b

  3. a, b and c

  4. all a, b, c and d

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Correct Option: C
Explanation:

Parsec, light year and micron are all units of length. 

Only second is the unit of time.

Debye is a unit of

physics measurements and units summary of si units fundamental quantities system of units

  1. rms velocity

  2. force

  3. specific gravity

  4. electric dipole moment

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Correct Option: D
Explanation:

The correct option is D.

The Debye, represented as D, is a CGS unit of electric dipole moment. This name was given in the honor of the physicist Peter J. W. Debye. Its value is defined as $1 \times { 10 } ^{ -18 }$ statcoulomb-centimetre.

The SI unit of luminous intensity is

physics measurements and units summary of si units fundamental quantities system of units

  1. Ampere

  2. Candela

  3. Mole

  4. None of these

Show answer
Correct Option: B
Explanation:

The SI unit of luminous intensity is Candela