Multiple Choice Questions on Waves
Here you can see solved Multiple Choice Questions included in the course of First Year Physics.
(1) When a waves goes from one medium to another medium, which of the following characteristic of the wave remain constant.
|(A) Volocity||(B) Frequency||(C) Wavelength||(D)Phase|
|(A) 0||(B) π/2||(C) π||(D) 2π|
|(A) doubled||(B) halved||(C) constant||(D) one-fourth|
Solution: The relation among the tension in the string, the mass per unit length of the string and velocity of the wave produced is given by
Now if tension is doubled, T = 2T and mass per unit length is halved, m = m/2. Put these values in the above equation.
|(A) reflection||(B) interference||(C) diffraction||(D) polarization|
(6) Which one of the following has no effect on the speed of sound in a gas?
|(A) Humidity||(B) Pressure||(C) Temperature||(D) Density|
EXPLANATION: See question 6 in comprehensive questions.
|(A) Longitudinal waves||(B) Transverse waves||(C) Progressive waves||(D) Stationary waves|
EXPLANATION: Energy cannot be transferred in case of stationary waves because at the node point, the particles of the medium are stationary. The standing (stationary) medium particle does not transfer the wave energy to the next particle of the medium.
|(A) 1.0× 106 Hz||(B) 1.0 × 109||(C) 1.0 × 1012||1.0 × 1015|
|(A) f||(B) 0.5f||(C) 2f||(D) 4f|
Solution: For the closed pipe,
Similarly, v = fλ ⇒ f = v/λ. Put in the above equation,
And for open pipe,
So f’ = v/λ’ now implies,
(11)If the amplitude of a wave is doubled, then its intensity is,
|(A) Doubled||(B) Halved||(C) Quadrupled||(D) One-fourth|
Explanation: Intensity of a wave is proportional to the amplitude of the wave. So when the amplitude doubles, intensity is quadrupled (i-e, becomes 4 times).
12. A sound source is moving towards a stationary listener with 1/10 of the speed of the sound. The ratio of apparent to real frequency is:
|(A) 11/10||(B) (11/10)2||(C) (9/10)2||(D) 10/9|
Solution: The apparent frequency is given by the relation,
[See question 9 (1).]
The ratio of frequencies is, therefore,
(From the above equation)
Put the values