Part-6 Waves Hard

A sound wave of wavelength 90 cm in glass is refracted into air. If the velocity of sound in glass is 5400 m/sec, the wavelength of the wave in air is -

A small piece of cork in a ripple tank oscillates up and down as ripples pass it. If the ripples travelling at 0.3 m/s have a wavelength of 1.5 p cm and the cork vibrates with an amplitude of 5 mm, the maximum velocity of the cork is -

Three waves of equal frequencies having amplitudes 10 μm, 4 μm and 7 μm arrive at a given point with successive phase difference of π/2. The amplitude of the resulting wave in μm is given by -

A vibrating tuning fork generates a wave given by y = 0.1 sin π(0.1x – 2t), where x and y are in metre and t in second. The distance travelled by the wave while the fork completes 30 vibrations is -

Velocity of sound in a gaseous medium is 330 ms^–1. If the pressure is increased by 4 times without change in volume, the velocity of sound in the gas is -

The ratio of intensities between two coherent sound source is 4 : 1. The difference of loudness in decibels (dB) between maximum and minimum intensities, when they interfere in space is -

The tension of a string is increased by 44%. If its frequency of vibration is to remain unchanged, its wavelength must be increased by -

The speed of sound wave in a gas, in which two waves of wavelengths 1.0 m and 1.02 m produce 6 beats per second is -

A tuning fork A produces 4 beats/second with another tuning fork B of frequency 288 Hz. When the fork A is loaded with a little wax. The beat frequency changes to 2. The frequency of the fork A before loading is (in Hz)-

Fork A (n_A = 50 Hz) produces 2 beats/sec with fork B, on filing A, beat frequency becomes 1, calculate n_b. -

The width of a certain spectral line at 500 nm is 2 × 10^–2 Approximately what is the largest path difference for which interference fringes produced by this light are clearly visible?

A mixture of light, consisting of wavelength 590 nm and an unknown wavelength, illuminates Young’s double slit and gives rise to two overlapping interference patterns on the screen. The central maximum of both lights coincide. Further, it is observed that the third bright fringe of known light coincides with the 4^th bright fringe of the unknown light. From this data, the wavelength of the unknown light is –

To prevent reflection from a camera lens, a thin film of magnesium is coated. In order that the light of wavelength 5000 Å not be reflected the minimum thickness of the film should be (m for magnesium = 1.25 and m for glass = 1.5) -

In placing a thin sheet of mica of thickness 12 × 10^–5 cm in the path of one of the interfering beams in YDSE, the central fringe shifts equal to a fringe width. Find the refractive index of mica. Given l = 600 nm -

Two sources give interference pattern which is observed on a screen, D distance apart from the sources. The fringe width is 2β. If the distance D is now doubled, then the fringe width will become -

In an interference experiment, third bright fringe is obtained on the screen with a light of 700 nm. What should be the wavelength of light source in order to obtain 5^th bright fringe at the same point -

In an interference experiment third bright is obtained on screen with light of 5000 Å. What should be the wavelength in order to obtain 4^th bright at same point -

Interference fringes were produced in Young's double slit experiment using light of wavelength 5000 Å. When film of thickness 2.5 × 10^–3 cm was placed over one slit, the fringe pattern shifts by a distance equal to 20 fringe width. The refractive index of film material is

In YDSE, the ratio of maximum and minimum intensities of fringe system is 4 : 1. The amplitudes of the coherent sources are in the ratio of -

Two coherent sources of intensity ratio 4 : 1 produce an interference pattern. The fringe visibility will be -

In Young's experiment, the ratio of maximum and minimum intensities in the fringe system is 9 : 1. The ratio of amplitudes of coherent sources is –

A closed organ pipe has length ‘’ The air in it is vibrating in 3^rd overtone with maximum amplitude ‘a’. The amplitude at a distance of /7 from closed end of the pipe is equal to–