10 Question-Answer on superposition of waves
1. Two waves of same frequency, travelling in the same medium, but in opposite direction, if superposed, give rise to
(a) Beats
(b) Standing waves
(c) Resonance
(d) Harmonics and overtones
Ans: ( b)
2. If the resultant amplitude due to superposition of two waves changes periodically with time as well as in position, then it is a case of:
(a) Stationary waves
(b) Beats
(c) Interference
(d) Lissajous figures
Ans: (a)
3. Two forks of frequencies 100 hz and 100.1 hz are vibrated to give Lissajous figures. The figures repeat their shapes in:
(a) 10 sec
(b) 1 sec
(c) 0.1 sec
(d) 0.5 sec
Ans: ( a)
4. Two periodic waves of amplitudes a and b pass through a region at the same time in the same direction. If a > b, the difference in the maximum and minimum possible amplitudes is :
(a) a + b
(b) a –b
(c) 2b
(d) 2a
Ans: (d)
5. Two waves of amplitude a each and same frequency travel in the same direction in a medium. The amplitude of the resultant wave is:
(a) Zero
(b) A
(c) 2a
(d) Between o and 2a
6. In a stationary wave
(a) Particles move a periodically
(b) All particles are at rest
(c) Amplitude is same at all places
(d) Amplitude is max. at some places and minimum at some other
Ans: ( d)
7. In the principle of superposition, the characteristic that gets added vectorially is:
(a) Displacement
(b) Velocity
(c) Amplitude
(d) Frequency
Ans: (a, c)
8. If two waves of same frequency and same amplitude, on superposition, produce a resultant disturbance of the same amplitude, the waves differ in the phase by:
(a) π
(b) 2π/3
(c) Zero
(d) π/3
Ans: ( b)
9. phase difference between two particles of a medium lying just on the opposite side of a node is:
(a) zero
(b) π/3
(c) π
(d) 2π
Ans: (c)
10. Two simple harmonic motions of same amplitude, same frequency and a phase difference of π/4 are superimposed at right angles to each other on a particle. The particle will describe a
(a) Circle
(b) Ellipse
(c) Figure of eight
(d) Straight line