Two particles are executing SHM of same amplitude and frequency along the same straight line path. They pass each other when going in opposite directions, each time their displacement is half of their amplitude. What is the phase difference between them? 


Correct option is








Two trains, one coming towards and another going away from an observer both at 4 m/s produce a whistle simultaneously of frequency 300 Hz. Find the number of beats produced?


A radio wave of frequency 840 MHz is sent towards an aeroplane. The frequency of the radio echo is 2.8 kHz more than the original frequency. Then the velocity of aeroplane is:



A whistle emitting a sound of frequency 440 Hz is tied to a string of 1.5 m length and rotated with an angular velocity of 20 rad/s in the horizontal plane. Then the range of frequencies heard by an observer stationed at a large distance from the whistle will be:

(v = 330 m/s):


Two whistles A and B produce notes of frequencies 660 Hz and 596 Hz respectively. There is a listener at the midpoint of the line joining them. Both the whistle B and the listener start moving with speed 30 m/s away from whistle A. If speed of sound be 330 m/s, how many beats will be heard by the listener?


Two sources A and B are sounding notes of frequency 680 Hz. A listener moves from A to B with a constant velocity u. If the speed of sound is 340 m/s, what must be the value of u so that he hears 10 beats per sec?


A source of sound of frequency 256 Hz is moving towards a wall with a velocity of 5 m/s. Velocity of sound is 330 m/s. The number of beats per second heard by an observer standing between the source and the wall is nearly:


A source of sound of frequency 256 Hz is moving towards a wall with a velocity of 5 m/s. The velocity of sound is 330 m/s. The number of beats heard by an observer moving along with the sounding object is:


A train has just completed a U-curve in a track which is a semi-circle. The engine is at the forward end of the semicircular part of the track while the last carriage is at the rear end of the semicircular track. The driver blows a whistle of frequency 200 Hz. Velocity of sound is 340 m/s. Then the apparent frequency as observed by a passenger in the middle of the train, when the speed of the train is 30 m/s, is:


A mass m is suspended separately from two springs of constants k1 andk2. Their time periods are found to be T1 and T2 respectively. If the same mass is suspended from the two springs connected in series, then the time period of the combination will be:



The figure below shows the wave y = A sin (ωt – kx), at any instant travelling in the +ve x-direction. What is the slope of the curve at B?