Constructive and destructive interference can be explained in terms of phase and path difference. Interference patterns can be calculated using wavelength, grating spacing and angle of maxima.

Which of the following wave properties can change during diffraction?

Direction

Frequency

Wavelength

What term is used to describe two waves when the crests and troughs of match as below?

In phase

Out of phase

Phase difference

Two waves are coherent, what characteristics do they share?

Zero or constant phase difference and frequency

Shape or similar shape and frequency

Zero or constant phase difference and colour

A coherent source produces two waves X and Y - which of the following path lengths of waves would produce constructive interference if the waves were to meet at a point?

A coherent source produces two waves X and Y - which of the following path lengths of waves would produce destructive interference if the waves were to meet at a point?

Green light is passed through a diffraction grating with 5000 lines per mm and bright fringes are observed on a screen 2 m away.

Which of the following would increase the fringe spacing on the screen?

Increasing the frequency of light to blue light

Replacing the grating with a grating having 7000 lines per mm

Moving the screen closer to 1.5 m from the grating

Microwave radiation of wavelength 40 mm passes through two slits P and Q on a metal sheet.

A microwave detector S detects points of maximum and minimum intensity in the region beyond the metal plate.

Which value of path difference PS - QS will produce constructive interference?

10 mm

40 mm

20 mm

Which value of path difference PS - QS will produce destructive interference?

60 mm

80 mm

Monochromatic light of wavelength 589 nm is incident on a grating - the spacing between lines on the grating is 4.8x10^{-6} m.

What is the angle between the zero order and first order maxima?

7.05°

6.89°

0.123°

What is the angle between the first order and second order maxima?

6.84°

7.16°