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If the kinetic energy of a particle becomes four times, then % change in momentum will be

a. 200b. 100c. 150d. 50Solution:Answer: (b)K.E. ⇒ K = P2 / 2mP ∝ √K... View Article

Three sound waves of equal amplitudes have frequencies (v-1), v, (v+1). They superpose to give beats. The number of beats produced per second will be

(a) 1(b) 2(c) 3(d) 4Solution: (b) 2Beat produced between(v-1) and v is 1.Beat produced between v and v+1 is 1. Beat produced between(v-1) and... View Article

When two sinusoidal waves moving at right angle to each other superimpose, they produce

(a) beats(b) Lissajous figure(c) interference(d) stationary wavesSolution: (b) Lissajous figureIf two SHMs act in perpendicular directions, then... View Article

Two coherent monochromatic beams of intensities I and 4I respectively are superposed. The maximum and minimum intensities in the resulting pattern are:

(a) 5I and 2I(b) 9I and I(c) 4I and 3I(d) 5I and ISolution: (b) 9I and IMaximum intensity = Imax = (√I1 + √I2)2Imax = (√4I + √I)2 = 9IMinimum... View Article

A sine wave is travelling in a medium. The minimum distance between the two particles, always having same speed, is

(a) λ/4(b) λ/3(c) λ/2(d) λSolution: (c) λ/2In a sine wave, the particles on the string vibrate in simple harmonic motion. The particles having... View Article

The ratio of speed of sound in Hydrogen to that in Oxygen at the same temperature is

(a) 16:1(b) 1: 4(c) 2:3(d) 4:1Solution: (d) 4:1Speed of sound in a medium = v = √(γP/ρ)For given temp, PH2 = PO2Also, γH2 = γO2ρ = m/VTherefore,... View Article

A particle on the trough of a wave at any instant will come to the mean position after a time. (T= time period)

(a) T(b) 2T(c) T/2(d) T/4Solution: (d) T/4Here T be the total time taken by a particle of wave to complete its one round.From mean to extreme,... View Article

When sound travels from air to water, the quantity that remains unchanged is:

(a) speed(b) wavelength(c) intensity(d) frequencySolution: (d) frequencyWhen sound travels from one medium to another the speed definitely... View Article

At a certain instant a stationary transverse wave is found to have maximum kinetic energy. The appearance of string at that instant is.

(a) Sinusoidal shape with amplitude A/3.(b) Straight line(c) Sinusoidal shape with amplitude A/2.(d) Sinusoidal shape with amplitude A.Solution:... View Article

A boat at anchor is rocked by waves whose crests are 100m apart and velocity is 25m/s. The boat bounces up once in every

(a) 2500 s(b) 75 s(c) 4s(d) 0.25 sSolution: (c) 4sThe boat bounces up, which means, it travels from crest to the consecutive crest along wave... View Article

The angle between particle velocity and wave velocity in transverse waves is

(a) zero(b) π/4(c) π/2(d) πSolution: (c) π/2In transverse waves the particles of the medium vibrate at right angles to the direction in which the... View Article

If the speed of a wave doubles as it passes from shallow water into deeper water, its wavelength will be

(a) unchanged(b) doubled(c) quadrupled(d) halvedSolution: (b) doubledSpeed = frequency × wavelength When a wave passes from one medium to the... View Article

A point source emits sound equally in all directions in a non-absorbing medium. Two points P and Q are at distances of 9m and 25m respectively from the source. The ratio of the amplitudes of the waves at P and Q is

(a) 9:4(b) 1: 22(c) 25:9(d) 625:81Solution: (c) 25:9I = P/4πr2 and I α A2And A α 1/rA1/A2 = r2/r1 = 25/9... View Article

The distance between two points differing in phase by 60^o on a wave having a wave velocity 360 m/s and frequency 500 Hz is

(a) 0.72 m(b) 0.18 m(c) 0.12m (d) 0.32mSolution: (c) 0.12m Wavelength of wave = velocity/frequency = 360/500 = 0.72 mDistance between two points... View Article

Sound waves transfer

(a) energy(b) Momentum(c) Both energy and momentum(d) only energy not momentumSolution: (c) Both energy and momentumSound waves transfer both... View Article

A wave of frequency 500 Hz has a velocity of 360 ms^-1. Calculate the distance between two points that are 60^o out of phase

(a) 12 cm(b) 18 cm(c) 17 cm(d) 25 cmSolution: (a) 12 cmwavelength = velocity/frequency = 360/500 = 72 cm60 degrees out of phase implies that the... View Article

Two Cu wires of radii R₁ and R₂ are such that (R₁>R₂). Then which of the following is true?

(a) Transverse wave travels faster in thicker wire(b) Transverse wave travels faster in thinner wire(c) Travels with the same speed in both the... View Article

When two waves of almost equal frequencies v₁ and v₂ reach at point simultaneously, the time interval between successive maxima is

(a) v1 - v2(b) v1 + v2(c) 1/(v1+v2)(d) 1/(v1-v2)Solution: (d) 1/(v1-v2)When two waves of almost equal frequencies v1 and v2 reach at point... View Article

Which quantity is transmitted with propagation of longitudinal waves through a medium?

(a) matter(b) energy(c) energy and matter(d) frequencySolution: (b) energyLongitudinal waves are propagated by propagation of energy by particles... View Article

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

(a) a sin(kx+ωt)(b) −a cos(kx−ωt)(c) −a cos(kx+ωt)(d) −a sin(kx−ωt)Solution: (c) −a cos(kx+ωt)Let us consider y = a cos(kx-ωt) and the other wave... View Article

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