Tag: motion and measurement

Questions Related to motion and measurement

Standard of unit is reproducible.

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: A
Explanation:

One of the properties of the units is standard unit should be reproducible. It means that the standard unit can be used repetitively to retain consistency of units, independent of space and time.

Hence, the given statement is true.

The unit of magnetic field is?

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

  1. Weber/m

  2. Weber$/m^2$

  3. Weber

  4. Weber $\times$ meter

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Correct Option: B
Explanation:

SI unit of magnetic field is  $Weber/m^2$. Other units of magnetic field are $Tesla$ and $Gauss$.
Also,  $1 \ Tesla = 10^4 \ Gauss$

SI Unit of intensity of light is: 

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

  1. Newton

  2. Kelvin

  3. Kilogram

  4. Candela

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Correct Option: D
Explanation:

Candela is the SI unit of intensity of light.

Which of the Quantity consists of unit as kg-m/sec ?

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

  1. Speed

  2. Momentum

  3. Acceleration

  4. Impulse

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Correct Option: B,D
Explanation:

1.  For Speed :

    $v = \dfrac{distance}{time} = m/sec$

2. For Momentum : 
   $P = m \times v$

   Units :  $kg - m/ sec$

3. For Acceleration :
    $a = \dfrac{\Delta v}{\Delta t}=m/{sec}^2$

4. For Impulse :
    $I =F\times \Delta t = \Delta p$
     Units : $N-sec  = (kg-m/{sec}^2) \times sec = kg-m/sec$

From above we can say that $Momentum$ and $Impulse$ have same unit as kg-m/sec.
      

What is the approximate diameter of human hair?

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

  1. $500$nm

  2. $5000$nm

  3. $50$nm

  4. $50000$nm

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Correct Option: D
Explanation:

Diameter of human hair is $50000$nm.

The unit kg $m^2s^{-2}$ is associated with

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

  1. Work

  2. Kinetic energy

  3. Potential energy

  4. All of these

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Correct Option: D
Explanation:

$kgm^2s^{-2}$ is the unit of energy. It's dimension is $[ML^2T^{-2}]$ All the quantities given in the option are different form of energy. So their units will be same. Then the unit $kgm^2s^{-2}$ is associated with all of the options.

Unit of power in S.I. system is

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

  1. Watt

  2. Calorie

  3. Newton

  4. Ergs

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Correct Option: A
Explanation:

Power is defined as the work done per unit time. So to get the SI unit of power :

$Power=\dfrac{Work}{Time}$

SI unit of Work $=$ Joules

SI unit of Time $=$ second

So S.I. unit of power $=\dfrac{Joule}{Second}=Watt$

The 'rad' is the correct unit used to report the measurement of

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

  1. the rate of decay of radioactive source

  2. the ability of a beam of gamma ray photons to produce ions in a target

  3. the energy delivered by radiation to a target

  4. the biological effect of radiation

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Correct Option: D
Explanation:

Rad is the unit of absorbed dose of ionizing radiation. One rad is equal approximately to the absorbed dose delivered when soft tissue is exposed to one-roentgen of medium-voltage radiation. Thus this is the bilogical effect of radiation.

Which of the following statements below should be followed while using the symbol for a unit of a physical quantity?

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

  1. The symbol named after scientist should have capital letter.

  2. They take plural forms.

  3. They can be written in full.

  4. They should be written only in the agreed symbols.

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Correct Option: A,C,D
Explanation:

1. They symbol named after scientist should have the capital letter, 

2. They can be written in full 
3. They should be written only in the agreed symbols be used while using the symbol for a unit of a physical quantity. 
4. They cannot take plural forms.

In CGS system, units of density is 

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

  1. kg/m$^3$

  2. gm/m$^3$

  3. kg/c.c

  4. gm/c.c

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Correct Option: D
Explanation:

The gram per cubic centimetre is a unit of density in the CGS system, defined as mass in grams divided by volume in cubic centimetres.