A person is listening to a tone of 500Hz sitting at a distance of 450 m from the source of the sound. What is the time interval between successive compressions from the source?

A siren is fitted on a car going towards a vertical wall at a speed of 36 kmh^(-1) . A person standing on the ground behind the car, listeners to the siren sound coming directly from the source as well as that coming after reflection from the wall. Calculate the apparant frequencies of both the sounds. Velocity of sound 340ms^(-1) , frequency of the siren 500Hz.

The instantaneous current from an a.c. source is given by I=5sim 314t . What is the r.m.s value of the current.

In a Young's double slit experiment, the slits are 0.03 cm apart and the screen is placed 1.5m away from the plane of the sources. The distance between the central bright fringe and the fourth bright fringe is measured to be 1 cm. Determine the wavelength of the light used.

An echo was heard after 3s. What is the distance of the reflecting surface from the source, given that the speed of sound is 342 ms^-1 ?

A person cannot see objects nearer than 1.2 m from his eyes. He wants for read a newspaper placed at a distance of 30 cm clearly. What is the nature and the power of lens required for this purpose?

A source of sound of frequency 500 Hz is moving towards an observer with velocity 30 m/s.The speed of the sound id 330 m/s.The frequency heard by the observer is

Three persons walk along a circle and require 10m, 15m and 18 m respectively to complete the circle. They start to walk along the circle from the same point and at the same time. Find after what time they meet again at the starting point for the first time.