Reflection from a Fixed End

Q.

A string of length 0.4 m and mass ${10}^{-2}$ kg is tightly clamped at its ends. The tension in the string is 1.6 N. Identical wave pulses are produced at one end at equal intervals of time $\Delta t$. The minimum value of $\Delta t$ which allows constructive interference between successive pulses is

1. 0.20 s

2. 0.05 s

3. 0.10 s

4. 0.40 s

Q. A wave represented by the equation y=acos(kx-wt) is superposed with another wave to form a stationary wave such that the point x=0 is a node. The equation for other wave is.

Q. $P$ is the junction of two wires $\text{A}$ and $\text{B}$. $\text{B}$ is made of steel and is thicker, while $\text{A}$ is made of aluminum and is thinner as shown in the figure$(i.e.{\mu }_B>{\mu }_A)$. If a wave pulse as shown in the figure approaches $P$, the reflected and transmitted waves from $P$ are respectively:

1. 
2. 
3. 
4. 

Q. 7. A man generates a symmetrical pulse in a string by moving his hands up and down .At t=0 the point in his hands moves downward.the pulse travel with 3ms on string abd his hands passes 6 times in each second from mean postion.then the point on string 3m will reach its upper extreme first time at time t

Q.

A string of length 0.4 m and mass ${10}^{-2}$ kg is tightly clampled at its ends. The tension in the string is 1.6 N. identical wave pulses are produced at one end at equal intervals of time ∆t. The minimum value of ∆t, which allows constructive interference between succesive pulses, is :

1. 0.05 s

2. 0.10 s

3. 0.20 s

4. 0.40 s

Q. A string of length $40\text{cm}$ and linear mass density $0.80\text{g/cm}$ is fixed at both ends and kept under a tension of $32\text{N}$. A wave pulse is produced near one of the ends at $t=0$, as shown in the figure, which makes periodic motion between the ends. What is the time after which the string will have the same shape shown in the figure?

1. After $0.03\text{sec}$
2. After $0.06\text{sec}$
3. After $0.05\text{sec}$
4. After $0.04\text{sec}$

Q. A star moving away from earth with a speed of $0.02c$, while emitting light of frequency $6\times {10}^{14}\text{Hz}$. What frequency will be observed on earth?
(Take $c=3\times {10}^8\text{m/s}$)

1. $0.12\times {10}^{14}\text{Hz}$
2. $0.24\times {10}^{14}\text{Hz}$
3. $5.88\times {10}^{14}\text{Hz}$
4. $1.2\times {10}^{14}\text{Hz}$

Q. When the reflection of a wave takes place which of the following qunatities may change ?

1. Frequency
2. Wavelength
3. Amplitude
4. Phase

Q. A sinusoidal wave represented by $y_i=0.3\cos (2x-40t)$ is travelling along a string towards a fixed end at $x=0$. Then, the equation of the reflected wave will be:-
(Assume there is no loss of energy at the boundary)

1. $0.3\cos (2x+40t+\frac{\pi }{2})$
2. $0.3\cos (2x-40t+\frac{\pi }{2})$
3. $0.3\cos (2x-40t+\pi )$
4. $0.3\cos (2x+40t-\pi )$

Q. A cylindrical tube, open at both ends, has fundamental frequency $n$. If one of the ends is closed, the fundamental frequency will become

1. $\frac{n}{2}$
2. $n$
3. $2n$
4. $4n$

Q. A sinusoidal wave represented by $y_i=0.3\cos (2x-40t)$ is travelling along a string towards a fixed end at $x=0$. Then, the equation of the reflected wave will be:-
(Assume there is no loss of energy at the boundary)

1. $0.3\cos (2x+40t+\frac{\pi }{2})$
2. $0.3\cos (2x-40t+\frac{\pi }{2})$
3. $0.3\cos (2x-40t+\pi )$
4. $0.3\cos (2x+40t-\pi )$