CBSE
Multiple Choice QuestionsThe driver of a car travelling with speed 30 ms-1 towards a hill sounds a horn of frequency 600 Hz. If the velocity of sound in air is 330 ms-1, the frequency of reflected sound as heard by driver is
550 Hz
555.5 Hz
720 Hz
720 Hz
The wave described by y = 0.25 sin (10 π x -2 πt), where x and y are in metre and t in second, is a wave travelling along the
- ve x direction with frequency 1 Hz
+ve x direction with frequency π Hz and wavelength λ = 0.2 m
+ve x direction with frequency 1 Hz and wavelength λ = 0.2 m
+ve x direction with frequency 1 Hz and wavelength λ = 0.2 m
Two sound waves with wavelengths 5.0 m and 5.5 m respectively, each propagate in a gas with velocity 330 m/s. We expect the following number of beats per second
12
0
1
1
A transverse wave propagating along x-axis is represented by:
where x is in metres and t is in seconds. The speed of the wave is
m/s
The time of reverberation of a room A is one second. What will be the time (in seconds) of reverberation of a room, having all the dimensions double of those of room A?
2
4
Which one of the following statements is true?
Both light and sound waves in air are transverse
The sound waves in air are longitudinal while the light waves are transverse
Both light and sound waves in air are longitudinal
Both light and sound waves in air are longitudinal
The two nearest harmonics of a tube closed at one end and open at other end are 220 Hz and 260 Hz. What is the fundamental frequency of the system?
10 Hz
20 Hz
30 Hz
30 Hz
Two soap bubbles coalesce. It is noticed that whilst joined together, the raddii of the bubbles are a and b where a>b. Then the radius of curvature of the interface between the two bubbles will be
a-b
a+b
ab/(a-b)
ab/(a+b)
If vibration of string is to be two times, then tension in the string must be made
Eight times
Four times
Twice
Half
A siren emitting sound of frequency 500 Hz is going away from a stationary listener with a speed of 50 m/s, the frequency of sound heard directly from the siren is
286.5 HZ
481 Hz
434.2 Hz
580 Hz
