Tag: physics

Questions Related to physics

The speed of sound in a certain medium is $960 m/s$. If $3600$ waves pass over a certain point in 1 minute, the wavelength is,

physics propagation of sound waves longitudinal vs transverse wave sound and light comparison of speed of sound with speed of light

  1. $2 m$

  2. $8 m$

  3. $4 m$

  4. $16 m$

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Correct Option: D

When a tuning fork of 500 Hz is used, the first and second resonating lengths of closed air column are found to be 18 cm and 54 cm respectively. Find the velocity of sound in S.I. system.

physics propagation of sound waves longitudinal vs transverse wave sound and light comparison of speed of sound with speed of light

  1. $120{ms}^{-1}$

  2. $240{ms}^{-1}$

  3. $360{ms}^{-1}$

  4. $480{ms}^{-1}$

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Correct Option: C

An observer measures speed of light to be C when he is stationary with respect to the source. If the observer moves with velocity $\displaystyle v$ towards the source then the velocity of light observed will be :

physics propagation of sound waves longitudinal vs transverse wave sound and light comparison of speed of sound with speed of light

  1. $\displaystyle c- v$

  2. $\displaystyle c + v$

  3. $\displaystyle \sqrt{1-v^2/c^2}$

  4. $\displaystyle c$

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Correct Option: D
Explanation:

Speed of light does not change with the frame of reference.  Option 'D' is correct.

The frequency of fundamental mode of vibration of an air column enclosed in a closed end pipe is 250 Hz. If its length is 33 cm, then find the velocity of sound in air.

physics propagation of sound waves longitudinal vs transverse wave sound and light comparison of speed of sound with speed of light

  1. $390 {ms}^{-1}$

  2. $160 {ms}^{-1}$

  3. $330 {ms}^{-1}$

  4. $150 {ms}^{-1}$

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Correct Option: C

A wave has a frequency of $5$ GHz.
What is the period of the wave?

physics propagation of sound waves longitudinal vs transverse wave sound and light comparison of speed of sound with speed of light

  1. $200$ ps

  2. $0.2$ ns

  3. $20$ ns

  4. $20000$ $\mu s$

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Correct Option: B
Explanation:

Given that,


Frequency $f=5 GHz=5\times10^{9}\ Hz$


The period of the wave is reciprocal of frequency.

$T=\dfrac{1}{f}$

$T=\dfrac{1}{5\times10^{9}}$

$T=2\times10^{-10}$

$T=0.2\ ns$

The period of the wave is $0.2\ ns$

Hence, B is correct option.

Which of the following product of $e, h, \mu, G$ (where $\mu$ is the permeability) be taken so that the dimensions of the product are same as that of the speed of light?

physics propagation of sound waves longitudinal vs transverse wave sound and light comparison of speed of sound with speed of light

  1. $h e^{-2} \mu^{-1} G^0$

  2. $h^2 e G^0 \mu$

  3. $h^0 e^2 G^{-1} \mu$

  4. $h G e^{-2} \mu^{0}$

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Correct Option: A

Which of the following does not has fundamental unit?

standardized measurement measurement of physical quantities need of unit for measurement measurements and experimentation physics

  1. Mass

  2. Time

  3. Force

  4. length

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Correct Option: C
Explanation:

The fundamental units are the units of the fundamental quantities, as defined by the International System of Units. They are not dependent upon any other units, and all other units are derived from them. There are seven basic fundamental quantities: Length, mass, time, electric current, amount of substance, luminous intensity & temperature. The quantities which are derived with the help of these basic physical quantities are called derived quantities. They are density, volume, pressure, force, etc.

The wavelength of light is usually expressed in

standardized measurement measurement of physical quantities need of unit for measurement measurements and experimentation physics

  1. Micron

  2. Fermi

  3. Nanometer

  4. Angstrom

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Correct Option: D
Explanation:

Angstrom $(\dot A)$ unit of length used chiefly in measuring wavelengths of light, equal to $10^{-10}$ metre, or $0.1$ nanometer.  It is used to express wavelengths of visible light, ultraviolet (UV) light, X rays, and gamma rays.

Which of the following is the largest unit of length?

standardized measurement measurement of physical quantities need of unit for measurement measurements and experimentation physics

  1. Light year

  2. Astronomical unit

  3. Parsec

  4. Nothing can be decided

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Correct Option: C
Explanation:

Parsec is the largest unit of length. It is usaed to measure the space distances.


$1\,Parsec=3.26$ light year

In a tug-of-war between the teams A and B, the rope breaks at a point which is nearer to A. Then

standardized measurement measurement of physical quantities need of unit for measurement measurements and experimentation physics

  1. A has applied more force

  2. B has applied more force

  3. A and B both have applied same force

  4. Neither has applied any force

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Correct Option: C