Tag: fundamental quantities

Questions Related to fundamental quantities

$\displaystyle N{ kg }^{ -1 }$ is the unit of 

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

  1. Retardation

  2. Acceleration

  3. Rate of change of velocity

  4. All of these

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Correct Option: D
Explanation:
Acceleration is measured as   $a = \dfrac{Force}{mass}$

Thus, $N kg^{-1}$ is the unit of acceleration.

Retardation is the acceleration in the opposite direction.

Also, acceleration is defined as rate of change of velocity of the body.
Thus option D is correct.

Unit for the rate of change of velocity is 

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

  1. $\displaystyle m/s$

  2. $\displaystyle { m }/{ { s }^{ 2 } }$

  3. $\displaystyle Ns$

  4. $\displaystyle N/s$

Show answer
Correct Option: B
Explanation:
Rate of change of velocity is known as acceleration.
Unit of acceleration is  $m/s^2$

Kilowatt hour $\left(kWh\right)$ represents the unit of

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

  1. Power

  2. Impulse

  3. Momentum

  4. Energy

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Correct Option: D
Explanation:
Kilowatt hour $(kWh)$ is the unit of energy.
$1 \ kWh = 3.6\times 10^6 \ J$

Which of the following physical quantities has no unit?

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

  1. Relative density

  2. Density

  3. Pressure

  4. Thrust

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Correct Option: A
Explanation:
Relative density is defined as the ratio of density of a given substance to the density of water.
Thus relative density has no unit.

Milligram is a submultiple of kilogram.

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

  1. True

  2. False

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Correct Option: A
Explanation:

Milligram is a submultiple of Kilogram.

Which is measured in hertz?  

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

  1. Frequency

  2. Amplitude

  3. Period

  4. Wavelength

  5. Kinetic Energy

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Correct Option: A
Explanation:

Frequency of a wave is measured in hertz  $(Hz)$.

Parallactic second is a unit of :

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

  1. Time

  2. Speed

  3. Distance

  4. None of these

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Correct Option: C
Explanation:

Parallactic second is a unit of distance.

Light year is the unit of time.

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

  1. True

  2. False

Show answer
Correct Option: B
Explanation:
One light year is defined as the distance travelled by light in vacuum on one year. So light year is the unit of distance.
So, the given statement is false.

The unit of absolute permitivity of a medium is 

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

  1. Joule/Coulomb

  2. Newton-Meter

  3. Farad/Meter

  4. Farad-Coulomb

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Correct Option: C
Explanation:

Absolute permittivity $(\epsilon)$ is the measure of the resistance that  is encountered when forming an electric field in a medium. The standard SI unit for absolute permittivity is Farad per meter $(F/m)$.

The temp of the sun is measured with

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

  1. platinum thermometer

  2. gas thermometer

  3. pyrometer

  4. vapour pressure

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Correct Option: C
Explanation:
A pyrometer is a non-contacting device that intercepts and measures thermal radiation, a process known as pyrometry. This device can be used to determine the temperature of an object's surface.  As the temperature of the sun is very high, a non-contact type temperature measurement is needed. So pyrometer will be used to measure the temperature of the sun.