CBSE
When an open organ is dipped in water upto half of its height, then its frequency will become
half
double
remain same
four time
A sound source producing waves of frequency 300 Hz and wavelength lm observer is stationary, while source is going away with the velocity 30 m is, then apparent frequency heared by the observer is
270 Hz
273 Hz
383 Hz
300Hz
When a stretched wire and a tuning fork are sounded together, 5 beats per second are produced, when length of wire is 95 cm or 100 cm, frequency of the fork is
90 Hz
100 Hz
105 Hz
195 Hz
A bat emitting an ultrasonic wave of frequency 4.5 x 10' Hz at speed of 6 m/s between two parallel walls. The two frequencies heared by the bat will be
4.67 x 104 Hz, 4.34 x 104 Hz
4.34 x 104 Hz, 4.67 x 104 Hz
4.5 x 104 Hz, 5.4 x 104 Hz
4.67 x 103 Hz, 4.34 x 104 Hz
A 4 kg block is suspended from the ceiling of an elevator through a spring having a linear mass density of 19.2 x 10-3 kg m-3 . Find the speed with respect to spring with which a wave pulse can proceed on the spring if the elevator accelerates up at the rate of 2.0 ms-2.
Take g = 10 ms-2
30 m/s
42 m/s
46 m/s
50 m/s
A wave packet with center frequency ω is propagating in dispersive medium with phase velocity of 1.5 x 103 m/s. When the frequency ω is increased by 2%, the phase velocity is found to decrease by 3 %. What is group velocity of the wave packet?
0.25 × 103 m/s
1.0 × 103 m/s
0.6 × 103 m/s
0.75 × 103 m/s
Linear density of a string of is 1.3 x 10-4 kg/m and wave equation is y = 0.021 sin (x + 30t ), Find, the tension in the string where, x in metre and t in second
0.12 N
0.21 N
1.2 N
0.012 N
Figure shows spring + block + pulley system which are light. The time period of mass would be
An observer is approaching with velocity v towards a light source. If the velocity of light is c, then velocity of light with respect to observer will be
c - v
c
c + v
A transverse wave is represented by the equation . For what value of is the particle velocity equal to two times the wave velocity