Tag: measurements and units

Quizzes (10) Questions (257)

Questions Related to measurements and units

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

The dimensional formula for magnetic flux is:

  1. $(ML^2T^{-2}A^{-1})$
  2. $(ML^3T^{-2}A^{-2})$
  3. $(M^0L^{-2}T^{2}A^{-2})$
  4. $(ML^2T^{-1}A^{2})$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The magnetic flux if given by

$\phi=BAcos\theta$
If $cos\theta=1$
The maximum magnetic flux, $\phi=BA$. . . . . .(1)
where, $B=$ magnetic field
$A=area$ 
The dimensional formula for magnetic field,
$F=qvB$
where, $v=$ velocity
$q=$ charge,
$B=$ magnetic field
$[B]=\dfrac{M^1 L^1T^{-2}}{[A^1 T^1][L^1T^{-1}]}$
$[B]=[M^1L^0T^{-2}A^{-1}]$
for area, $[A]=[M^0 L^2 T^0]$
The dimensional formula for magnetic flux,
$[\phi]=[M^1L^0 T^{-2}A^{-1}].[M^0L^2T^0]$
$[\phi]=[M^1L^2T^{-2}A^{-1}]$
The correct option is A.

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

The SI unit of gravitational potential is :

  1. Joule/kg
  2. Joule$^2$/kg

  3. kg/Joule
  4. Joule/kg$^2 $
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The gravitational potential at a point is the potential energy associated with a unit mass due to its position in the gravitational field of another body. Gravitational potential is the amount of work done in bringing a body of unit mass from infinity to that point.
Gravitational potential (V) $=\dfrac{Work done}{Mass}=\dfrac{W}{m}$
Gravitational potential  is a scalar quantity and the  SI unit is $J/kg$. 

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

The SI unit of $ \dfrac{1}{2 \pi \sqrt{LC}}$ is equivalent to that of :

  1. time period

  2. frequency

  3. wavelength

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

The angular frequency of current oscillations in an LC circuit is given by $\omega =\dfrac{1}{\sqrt {LC}}$ and $\omega = 2\pi f$.
$\Rightarrow f= \dfrac{1}{2\pi \sqrt{LC}}$ and the unit is equivalent to that of frequency.

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

Rate of energy dissipation is measured in 

  1. Watt

  2. Joule

  3. Weber

  4. Joule / coulomb
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Power, or the rate of energy dissipation, is defined as energy per unit time and is measured in Watts (where 1 Watt equals 1 Joule per second). Joules measure energy, Weber measures magnetic flux, and Joule per coulomb measures electric potential.

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

Which of the following does not has fundamental unit?

  1. Mass

  2. Time

  3. Force

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

The fundamental units are defined arbitrarily and they are used to derive of others unit. Generally the most common fundamental units are mass, time, length and current.

As the unit of force can be derived from three fundamental units, mass, length and time so the force does not has fundamental unit.