4.4 Wave Behaviour

When two waves of the same frequency and amplitude overlap and interfere constructively, the resulting amplitude is:

A. Halved

B. The same as the original waves

C. Doubled

D. Zero

In a double-slit experiment, the central maximum is observed to be:

A. The brightest and widest fringe

B. The dimmest and narrowest fringe

C. The same brightness and width as other fringes

D. Absent

Which of the following best describes destructive interference?

A. Two waves combine to produce a wave of greater amplitude.

B. Two waves combine to produce a wave of zero amplitude.

C. Two waves pass through each other without any change.

D. Two waves combine to produce a wave of half the original amplitude.

In a single-slit diffraction experiment, as the width of the slit decreases, the width of the central maximum:

A. Increases

B. Decreases

C. Remains the same

D. Becomes zero

The superposition principle states that:

A. Waves can pass through each other without any change.

B. The displacement of a medium caused by two or more waves is the algebraic sum of the displacements caused by each wave.

C. Waves always interfere constructively.

D. Waves always interfere destructively.

a) Two waves of the same frequency and amplitude travel in the same direction and overlap. If the phase difference between them is pi radians, describe the type of interference that occurs. [2]

b) Given that the wavelength of the waves is 0.5 m and the speed of the waves is 2 m/s, calculate the frequency of the waves. [2]

a) A single slit diffraction experiment is set up using monochromatic light. Explain why a central maximum is observed on the screen. [2]

b) If the width of the single slit is doubled, describe the effect this will have on the width of the central maximum. [2]

a) In a double-slit experiment, the path difference between the waves from the two slits is equal to half the wavelength. What type of interference is observed at this point? [2]

b) Given that the slit separation is 0.1 mm and the screen is placed 2 m away from the slits, calculate the wavelength of the light used if the first order bright fringe is observed 1 mm away from the central maximum. [2]

a) Two coherent light sources produce waves that overlap at a point P. If the path difference between the waves reaching P is three-quarters of the wavelength, what type of interference occurs at P? [2]

b) Define the term 'diffraction'. [2]

c) A single slit diffraction experiment is set up with a slit width of 0.1 mm. If the wavelength of the light used is 500 nm, calculate the angle at which the first minimum occurs. [3]

a) Describe the difference between constructive and destructive interference in terms of phase difference. [2]

b) In a double-slit experiment, the distance between the slits is 0.3 mm. If the first order bright fringe is observed 1 mm away from the central maximum on a screen placed 2 m away, calculate the wavelength of the light used. [3]

c) Explain why diffraction is more noticeable with longer wavelengths. [2]