Class 12 Wave Optics CBSE Questions & Answers

The refractive index of glass is 1.5. What is the speed of light in glass? (Speed of light in vacuum is 3.0\( \times {\rm{ 1}}{0^{\rm{8}}}{\rm{m }}{{\rm{s}}^{-{\rm{1}}}}\))

The refractive index of glass is 1.5 which of the two colors red and violet travels slower in a glass prism?

In a Young’s double-slit experiment, the slits are separated by 0.28 mm and the screen is placed 1.4 m away. The distance between the central bright fringe and the fourth bright fringe is measured to be 1.2 cm. Determine the wavelength of light used in the experiment

In Young’s double-slit experiment using monochromatic light of wavelength l, the intensity of light at a point on the screen where path difference is \(\lambda \), is K units. What is the intensity of light at a point where path difference is \(\lambda \) /3?

A beam of light consisting of two wavelengths, 650 nm and 520 nm, is used to obtain interference fringes in a Young’s double-slit experiment. Find the distance of the third bright fringe on the screen from the central maximum for wavelength 650 nm.

A beam of light consisting of two wavelengths, 650 nm and 520 nm, is used to obtain interference fringes in a Young’s double-slit experiment. What is the least distance from the central maximum where the bright fringes due to both the wavelengths coincide?

In a double-slit experiment the angular width of a fringe is found to be \(0.{\rm{2}}^\circ \) on a screen placed 1 m away. The wavelength of light used is 600 nm. What will be the angular width of the fringe if the entire experimental apparatus is immersed in water? Take refractive index of water to be 4/3.

What is the Brewster angle for air to glass transition? (Refractive index of glass = 1.5.)

Light of wavelength 5000 Å falls on a plane reflecting surface. What are the wavelength and frequency of the reflected light? For what angle of incidence is the reflected ray normal to the incident ray?

Estimate the distance for which ray optics is good approximation for an aperture of 4 mm and wavelength 400 nm.

The 6563 \(\mathop A\limits^0 {\rm{ H}}\alpha \) line emitted by hydrogen in a star is found to be redshifted by 15 \(\mathop A\limits^0 \). Estimate the speed with which the star is receding from the Earth.

In double-slit experiment using light of wavelength 600 nm, the angular width of a fringe formed on a distant screen is \(0.{\rm{1}}\). What is the spacing between the two slits?

Two towers on top of two hills are 40 km apart. The line joining them passes 50 m above a hill halfway between the towers. What is the longest wavelength of radio waves, which can be sent between the towers without appreciable diffraction effects?

A parallel beam of light of wavelength 500 nm falls on a narrow slit and the resulting diffraction pattern is observed on a screen 1 m away. It is observed that the first minimum is at a distance of 2.5 mm from the centre of the screen. Find the width of the slit.

Two plane mirrors intersect at right angles. A laser beam strikes the first of them at a point 11.5 cm from their point of intersection, as shown in figure For what angle of incidence at the first mirror will this ray strike the midpoint of the second mirror (which is 28.0 cm long) after reflecting from the first mirror?