Wave Optics quiz

According to Huygens' principle, each point on a wavefront acts as:

Coherent sources have:

The fringe width in Young's experiment is:

The width of the central maximum in single slit diffraction is:

Polarisation of light proves that light is:

Brewster's law is:

Malus' law states that I equals:

Unpolarised light of intensity I0 passing through a polaroid has intensity:

When light passes from air into glass, its frequency:

If Young's apparatus is immersed in water, the fringe width:

Why can two independent sodium lamps not produce interference fringes? (2 marks)

What is the shape of the wavefront from (i) a point source and (ii) a distant star? (2 marks)

Why is diffraction of sound waves more noticeable than that of light waves? (2 marks)

What happens to the interference pattern if one slit is covered? (2 marks)

Why does the sky appear partially polarised? (2 marks)

At Brewster's angle, what is the angle between the reflected and refracted rays? (2 marks)

Why does the intensity of secondary maxima in single slit diffraction decrease? (2 marks)

Write the expression for the position of the nth bright fringe in Young's experiment. (2 marks)

Explain why white light gives coloured fringes in Young's experiment with a white central fringe. (2 marks)

Give two uses of polaroids. (2 marks)

In Young's experiment, lambda = 500 nm, d = 0.5 mm and D = 1 m. Find the fringe width. (3 marks)

The fringe width in Young's experiment is 0.4 mm in air. Find it when the apparatus is immersed in water (n = 4/3). (3 marks)

In single slit diffraction, the first minimum for light of wavelength 600 nm occurs at 30 degrees. Find the width of the slit. (3 marks)

Find Brewster's angle for water of refractive index 1.33 (tan 53.1 degrees = 1.33). Find the angle of refraction at this angle of incidence. (3 marks)

Polarised light passes through an analyser. At what angle between the polariser and analyser axes is the transmitted intensity one-fourth of its maximum value? (3 marks)

Read the passage and answer the questions. Fishermen and drivers wear polaroid sunglasses to reduce glare from water surfaces and wet roads. Light reflected from these surfaces is largely polarised. (i) How does reflection polarise light? (ii) How do polaroid sunglasses reduce glare? (iii) At what angle is the reflected light completely polarised for water (n = 1.33)? (5 marks)

Read the passage and answer the questions. In a laboratory, a student performs Young's double slit experiment with sodium light (589 nm), slits 0.5 mm apart and a screen 1.0 m away. (i) Find the fringe width. (ii) What happens if the screen is moved to 2.0 m? (iii) What happens if a thin transparent sheet covers one slit? (5 marks)

Read the passage and answer the questions. We can hear people talking around a corner of a building but cannot see them, even though both sound and light are waves. (i) Name the phenomenon involved. (ii) Why is it more noticeable for sound? (iii) What condition on the size of the obstacle is needed for light? (5 marks)

Read the passage and answer the questions. A plane wavefront of light travels from air into glass of refractive index 1.5 at an angle. Using Huygens' construction, a student shows that the refracted wavefront bends towards the normal. (i) Find the speed of light in glass. (ii) What happens to the wavelength? (iii) Why does the wavefront bend? (5 marks)

Read the passage and answer the questions. LCD screens of calculators and watches use polarising films. When viewed through a polaroid that is rotated, the display becomes dark at certain angles. (i) Why does the display become dark? (ii) What does this show about the light from the LCD? (iii) State Malus' law. (5 marks)

State Huygens' principle and use it to derive the laws of reflection and refraction, with diagrams. (6 marks)

Describe Young's double slit experiment and derive the expression for the fringe width. (6 marks)

Explain diffraction of light at a single slit with a diagram. Derive the conditions for minima and the width of the central maximum. (6 marks)

Explain polarisation of light by polaroids, state Malus' law and explain how the intensity varies when an analyser is rotated, with a graph. (6 marks)

Explain polarisation by reflection and derive Brewster's law with a diagram. (6 marks)