The driver of a car travelling with speed 30 m/s towards a hill sounds a horn of frequency 600 Hz. If the velocity of sound in air is 330 m/s, the frequency of reflected sound as heard by driver is

A wave in a string has an amplitude of 2 cm. The wave travels in the +ve direction of x axis with a speed of 128 m/s. and it is noted that 5 complete waves fit in 4m length of the string. The equation describing the wave is

A point performs simple harmonic oscillation of period T and the equation of motion is given by x = a sin($$\omega $$t + $$\pi $$/6). After the elapse of what fraction of the time period the velocity of the point will be equal to half of its maximum velocity?

Two periodic waves of intensities $$I$$₁ and $$I$$₂ pass through a region at the same time in the same direction. The sum of the maximum and minimum intensities is