Tag: from moving to stationary

Questions Related to from moving to stationary

In strings, the position of antinodes are obtained at

physics superposition of waves-2: stationary (standing) waves: vibrations of air columns from moving to stationary stationary (or standing) waves formation of stationary waves

  1. $\lambda,\space2\lambda, \space3\lambda$

  2. $0,\space\lambda,/2 \space\lambda$

  3. $2\lambda,\space4, \space6\lambda$

  4. $\lambda/4,\space3\lambda/4, \space5\lambda/4$

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Correct Option: D
Explanation:

In a string which is connected at both ends (similarity to sine wave), anti-nodes appear at odd multiples of $\dfrac{\lambda}{4}$.

If four loops are formed n a string of length $80$ cm, then the wavelength of stationary wave will be 

physics superposition of waves-2: stationary (standing) waves: vibrations of air columns from moving to stationary stationary (or standing) waves formation of stationary waves

  1. $0.2$ m

  2. $0.6$ m

  3. $0.8$ m

  4. $0.4$ m

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Correct Option: A

Equation of a standing wave is expressed as $y=2A\sin { \omega t } \cos { kx } $. In the equation, quantity $\omega /k$ represents 

physics superposition of waves-2: stationary (standing) waves: vibrations of air columns from moving to stationary stationary (or standing) waves formation of stationary waves

  1. $the\ transverse\ speed\ of\ the\ particles\ of\ the\ string.$

  2. $the\ speed\ of\ the\ component\ waves.$

  3. $the\ speed\ of\ the\ standing\ wave.$

  4. $a\ quantity\ that\ is\ independent\ of\ the\ properties\ of\ the\ string.$

Show answer
Correct Option: C
Explanation:

Equ of standing wave is $y=2A \sin wt \cos Kx$. The quantity $\dfrac { W }{ K } $ always represent the speed of the wave.


Hence Option (C) is correct.

Energy is not propogated by:

physics superposition of waves-2: stationary (standing) waves: vibrations of air columns from moving to stationary stationary (or standing) waves formation of stationary waves

  1. Stationary waves

  2. Electromagnetic waves

  3. Longitudinal progressive waves

  4. transverse progressive waves

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Correct Option: A
Explanation:

Stationary wave is also known as standing wave. It remains in a constant position. Two opposing waves combine to form a standing wave. Hence energy is not propagated in stationary wave.

Energy is not carried by

physics superposition of waves-2: stationary (standing) waves: vibrations of air columns from moving to stationary stationary (or standing) waves formation of stationary waves

  1. transverse progressive wave

  2. longitudinal progressive wave

  3. transverse stationary wave

  4. electromagnetic wave

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Correct Option: C
Explanation:

The main difference between stationary and progressive waves is: Progressive waves transfer energy from one place to another, without transferring matter and Stationary waves do not transfer energy from one place to another. Clearly only one option has stationary waves.

Energy is not carried by which of the following wave?

physics superposition of waves-2: stationary (standing) waves: vibrations of air columns from moving to stationary stationary (or standing) waves formation of stationary waves

  1. Progressive

  2. Electromagnetic

  3. Transverse

  4. Stationary

Show answer
Correct Option: D
Explanation:

Stationary waves do not carry energy with it as it is stationary or does not change position.

List - I                                                        List - II
a)  Phase difference                                 e) $\pi $
between two particles in
 alternate loops.
b)  Phase difference                                 f)  $\displaystyle \frac{\pi}{2}$
 between two particles in
successive loops
c)  Phase difference between                g) $2\pi $
two particles in the same loop
d)  Phase difference between                h) $0$
$Y _{1}=a\sin (\omega t-Kx)$
$Y _{2}=a\cos (\omega t-Kx)$

physics superposition of waves-2: stationary (standing) waves: vibrations of air columns from moving to stationary stationary (or standing) waves formation of stationary waves

  1. a-g, b-e, c-h, d-f

  2. a-e, c-f, d-g, e-h

  3. a-f, b-e, c-g, d-h

  4. a-g, b-e, c-f, d-h

Show answer
Correct Option: A
Explanation:

a ) Two particles in alternate loops refers to particles having same phase and direction
$\therefore $ phase difference is $2\pi $
b ) Two particles in successive loops differs in phase by $\pi $ 
c ) Two particles in same loop are always in phase $\Rightarrow $ phase difference is $0$.
d ) $y _1= a  \sin  (\omega t-kx)$
$y _2= a  \cos  (\omega t-kx)$
$= a  \sin (\omega t-kx +\dfrac{\pi}{2})$
$\Rightarrow $ phase difference is $ \dfrac{\pi }{2}$.

Mark incorrect Statement 

physics superposition of waves-2: stationary (standing) waves: vibrations of air columns from moving to stationary stationary (or standing) waves formation of stationary waves

  1. Magnitude of strain is maximum at antinode because medium particles at antinodes have maximum possible velocity

  2. Nodes and antinodes form in case of stationary waves only.

  3. In case of stationary waves maximum pressure change occurs at antinode.

  4. Due to propagation of longitudinal wave in air maximum pressure change is equal to $\dfrac{2\pi fs _{0}}{\rho v}.$ ($f$ : frequency, $s _{0}$ : maximum displacement, $\rho$ : density of medium, $v $: speed of wave)

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Correct Option: A,B,C,D
Explanation:

(A) Magnitude of strain is maximum at antinode because medium particles at antinodes have minimum possible velocity.
(B) Nodes and antinodes form in case of travelling waves also.
(C) In case of stationary waves maximum pressure change occurs at node.
(D) Due to propagation of longitudinal wave in air maximum pressure change is equal to $2\pi f s _{0}\rho V$.

Assertion - In a stationary wave, no transfer of energy takes place.
Reason - There is no onward motion of the disturbance from one particle to adjoining particle in stationary wave.

physics superposition of waves-2: stationary (standing) waves: vibrations of air columns from moving to stationary stationary (or standing) waves formation of stationary waves

  1. Assertion and Reason are correct and Reason is the correct explanation for Assertion

  2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion

  3. Assertion is correct but Reason is incorrect

  4. Both Assertion and Reason are incorrect

Show answer
Correct Option: B
Explanation:

In stationary wave, total energy associated with it is twice the energy of each of incident and reflected wave. large amount of energy are stored equally in standing wave and became trapped with wave. Hence there is no transmission of energy through the waves.

As two students holds opposite ends of slinky that is the resting on the floor, one student shakes the end he is holding back and forth with the constant frequency. He later shakes exactly the same way but with a much greater frequency.
Which statement best describes other changes that take place as a result of this increased frequency?

physics superposition of waves-2: stationary (standing) waves: vibrations of air columns from moving to stationary stationary (or standing) waves formation of stationary waves

  1. The wave speed and the wavelength both increases.

  2. The wave speed increases, but the wavelength does not significantly change.

  3. The wavelength increases ,but the wave speed does not significantly change.

  4. The wave speed decreases, but the wavelength does not significantly change.

  5. The wavelength decreases ,but the wave speed does not significantly change.

Show answer
Correct Option: A
Explanation:

We know that frequency of a wave is characterized by the source of wave . In both the cases wave in the slinky has a constant frequency but not same in both cases  , 

now we have $v=f\lambda$ ,
or                  $f=v/\lambda$ , 
when frequency $f$ is  increased in second case , wave speed $v$ increases and to maintain a constant frequency $f$ (to maintain a constant ratio), wavelength $\lambda$ also increases
 .