Physics Test 19...

A siren emitting a sound of frequency 800 Hz moves away from an observer towards a cliff at a speed of 15ms⁻¹. Then, the frequency of sound that the observer hears in the echo reflected from the cliff is

(Take velocity of sound in air=330ms⁻¹)

A source of sound S emitting waves of frequency 100 Hz and an observer O are located at some distance from each other. The source is moving with a speed of 19.4 m s'1 at an angle of 60° with the source observer line as shown in the figure. The observer is at rest.

The apparent frequency observed by the observer(velocity of sound in air 330ms⁻¹), is

The number of possible natural oscillations of air column in a pipe closed at one end of length 85 cm whose frequencies lie below 1250 Hz are

(Velocity of sound = 340ms⁻¹)

If we study the vibration of a pipe open at both ends, then the following statement is not true.

Two sources of sound placed close to each other, are emitting progressive waves given by y₁ = 4sin600πt and y₂ = 5sin608πt An observer located near these two sources of sound will hear

A geostationary satellite is orbiting the earth at a height of 5R above that surface of the earth, R being the radius of the earth. The time period of another satellite in hours at a height of 2R from the surface of the earth is

A particle of mass m is thrown upwards from the surface of the earth, with a velocity u. The mass and the radius of the earth are, respectively, M and R.G is gravitational constant and g is acceleration due to gravity on the surface of the earth. The minimum value of u so that the particle does not return back to earth, is

A simple pendulum bob has a mass "m" and length "L". The bob is drawn aside such that the string is horizontal and then it is released. The velocity of the bob while it crosses the equilibrium position is

A simple pendulum is made by attaching a 1 kg bob to a 5 m long copper wire. Its period is T. Now, if 1 kg bob is replaced by 10 kg bob, the period of oscillation

A body executes simple harmonic motion. The potential energy (PE), the kinetic energy (KE) and total energy (TE) are measured as function of displacement x. Which of the following statement is true?