Diagram 1 shows a ripple tank experiment in which plane waves are diffracted through a narrow slit in a metal sheet. Diagram 2 shows the same tank with a slit of greater width. In each case, the pattern of the waves incident on the slit and the emergent pattern are shown. Which action would cause the waves in diagram 1 to be diffracted less and so produce an emergent pattern closer to that shown in diagram 2 ?

increasing the frequency of vibration of the bar

increasing the speed of the waves by making the water in the tank deeper

reducing the amplitude of vibration of the bar

reducing the length of the vibrating bar

Physics

IGCSE&ALevel

CAIE

Exam No：9702_s10_qp_13 Year：2010 Question No：25

Answer:

Knowledge points:

8.1.1 explain and use the principle of superposition in simple applications

8.1.2 show an understanding of experiments that demonstrate stationary waves using microwaves, stretched strings and air columns

8.1.3 explain the formation of a stationary wave using a graphical method, and identify nodes and antinodes

8.2.1 explain the meaning of the term diffraction

8.2.2 show an understanding of experiments that demonstrate diffraction including the diffraction of water waves in a ripple tank with both a wide gap and a narrow gap

8.3.1 understand the terms interference and coherence

8.3.2 show an understanding of experiments that demonstrate two-source interference using water ripples, light and microwaves

8.3.3 understand the conditions required if two-source interference fringes are to be observed

8.3.4 recall and solve problems using the equation m = $\frac{ax}{n}$ for double-slit interference using light

8.4.1 recall and solve problems using the formula d sin i = nm

8.4.2 describe the use of a diffraction grating to determine the wavelength of light (the structure and use of the spectrometer are not included)

Answer:

Knowledge points:

Solution:

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