Tag: physics

Questions Related to physics

Consider the following two equations $L=I\omega$ and $ \dfrac { dL }{ dt } =\Gamma $. In noninertial frames :

  1. both A and B are true

  2. A is true but B is false

  3. B is true but A is false

  4. both A and B are false.


Correct Option: B

The equation $y = a \sin^2 \left(2 \pi nt - \dfrac{2\pi x}{\lambda}\right)$ represents a wave with

  1. Amplitude $a$, frequency $n$ and wavelength $\lambda$

  2. Amplitude $a$, frequency $2n$ and wavelength $2\lambda$

  3. Amplitude $a/2$, frequency $2n$ and wavelength $\lambda$

  4. Amplitude $a/2$, frequency $2n$ and wavelength $\lambda/2$


Correct Option: D

The speed of the wave travelling on the uniform circular hoop of string, rotating clockwise in absence of gravity with tangential speed $v _0$, is :

  1. $v=v _0$

  2. $v=2v _0$

  3. $v=\dfrac{v _0}{\sqrt 3}$

  4. $v=\dfrac{v _0}{2}$


Correct Option: A

The equation $y =A\cos^2\left(2\pi\, nt -2\pi \dfrac{x}{\lambda}\right)$ represents a wave with

  1. amplitude $A/2$, frequency $2n$& wavelength $\lambda/2$

  2. amplitude $A/2$, frequency $2n$& wavelength $\lambda$

  3. amplitude $A$, frequency $2n$& wavelength $2\lambda$

  4. amplitude $A$, frequency $n$& wavelength $\lambda$


Correct Option: A

The equation of a wave is given by 
$ Y\quad =\quad A\quad sin\quad \omega \left( \frac { x }{ v } -k \right)  $
Where $ \omega $ is the angular velocity and v is the linear velocity.The dimensions of K is

  1. LT

  2. T

  3. $ T^{-1} $

  4. $ T^2 $


Correct Option: B

The equation of a progressive wave is $Y= a sin(200 t-x)$, where x is in meter and t is in second. The velocity of wave is

  1. $200 $ m/sec

  2. $100 $ m/sec

  3. $50 $ m/sec

  4. None


Correct Option: A

The equation of a wave travelling on a stretched string is :
$y=4\sin 2\pi \left(\dfrac{t}{0.02}-\dfrac{x}{100}\right)$
Here $x$ and $y$ are in $cm$ and $t$ is in second. the relative deformation amplitude of medium is :

  1. $0.02\pi$

  2. $0.08\pi$

  3. $0.06\pi$

  4. $none\ of\ these$


Correct Option: B

A wave has a wavelength of 3m. The distance between a crest and adjacent trough is

  1. 0.75 m

  2. 1.5 m

  3. 3 m

  4. 1 m


Correct Option: C

A source oscillates with a frequency 25 Hz and the wave propagates with 300 m/s. Two points A and B are located at distances 10 m and 16 m away from the source. The phase difference between A and B is 

  1. $\displaystyle \frac{\pi}{4}$

  2. $\displaystyle \frac{\pi}{2}$

  3. $\pi$

  4. $2 \pi$


Correct Option: C
Explanation:

Wavelength of the wave=$\lambda=\dfrac{v}{\nu}=\dfrac{300}{25}=12m$

Distance between the two points=$16m-10m=6m=\dfrac{\lambda}{2}$
$=\dfrac{2\pi}{\lambda}\dfrac{\lambda}{2}=\pi$

Two simple harmonic motions are represented by the equations 
$y _1=10\sin \left(3\pi t+\dfrac{\pi}{4}\right)$
and $y _2=5(3\sin 3\pi t+\sqrt 3 \cos 3\pi t)$ Their amplitudes are in the ratio of :

  1. $\sqrt 3$

  2. $1/\sqrt 3$

  3. $2$

  4. $1/6$


Correct Option: B