Due to Doppler effect, the shift in the wavelength observed is 0.1 Å, for a star producing a wavelength 6000 Å. The velocity of recession of the star will be  


Correct option is


Doppler shift in wavelength is given by




A particle is executing simple harmonic motion along the x-axis with amplitude 4 cm and time period 1.2 s. The minimum time taken by the particle to move from x = +2 cm to x = +4 cm and back again is



Two waves are represented by the following equations:


The ratio of intensities I2/I1 will be


The velocity of sound in a diatomic gas is 300 ms–1. What is the rms velocity of its molecules?  


The length of a sonometer wire AB is 100 cm. Where should the two bridges be placed from end A to divide the wire in three segments whose fundamental frequencies are the ratio of 1:2:3?


A toothed wheel is rotated at 120 r.p.m. A post card is placed against the teeth. How many teeth must the wheel have to produce a note whose pitch is the same as that of a tuning fork of frequency 256 Hz?


If a spring extend by x on loading, then the energy stored in the spring is (T is the tension in the spring and k its force constant)


A pulse travels along a stretched string and reaches the fixed end of the string. It will be reflected back with


At which temperature will the velocity of sound at 27oC become double?



The equation of a travelling wave is


Where y is the microns, t in seconds and x in metres. The ratio of the maximum particle velocity and velocity of the wave is


A particle, with restoring force proportional to displacement and damping force proportional to velocity is subjected to a force F sin ωt. If the amplitude of the particle is maximum at ω = ω1 and its energy is maximum at ω = ω2, then (ω0 is the angular frequency of natural oscillations of the particle)