The equation of a progressive wave can be given by $$y = 15\sin (660\pi t - 0.02\pi x)$$ cm. The frequency of the wave is

A hollow cylinder with both sides open generates a frequency f in air. When the cylinder vertically immersed into water by half its length the frequency will be

Two stretched strings have lengths l and 2l while tensions are T and 4T respectively. If they are made of same material the ratio of their frequency is

When sound is produced in an aeroplane with a velocity of 200 m/s horizontally its echo is heard after $$10\sqrt 5 $$ seconds. If velocity of sound in air is 300 ms^$$-$$1 the elevation of aircraft is

Two turning forks of frequencies n₁ and n₂ produces n beats per second. If n₂ and n are known, n₁ may be given by

A car moving with a velocity of 36 km/hr crosses a siren of frequency 500 Hz. The apparent frequency of siren after passing it will be

The equation of a stationary wave along a stretched string is given by $y=5 \sin \frac{\pi x}{3} \cos 40 \pi t$. Here $x$ and $y$ are in cm and $t$ in second. The separation between two adjacent nodes is

Longitudinal waves cannot

The displacement of a plane progressive wave in a medium, travelling towards positive x-axis with velocity 4 m/s at t = 0 is given by $$y = 3\sin 2\pi \left( { - {x \over 3}} \right)$$. Then the expression for the displacement at a later time t = 4 sec will be

A wave disturbance in a medium is described by $y(x, t)=0.02 \cos \left(50 \pi t+\frac{\pi}{2}\right) \cos (10 \pi x)$ where $x, y$ are in meters and $t$ is in second. Which statement(s) is/are correct?