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Two learners investigate the effect of the slit width on the degree of diffraction. They use a green light with a wavelength 520 nm. They set up an experiment, as shown below, and measure the position of the first dark line from the centre of the bright, central band when changing the slit width.
The following results are obtained:
7.1 State Huygens’ principle in words. (2)
7.2 For this experiment, write down:
7.2.1 The independent variable (1)
7.2.2 The dependant variable (1)
7.2.3 ONE controlled variable (1)
7.3 Give a conclusion for the results obtained in this experiment. (2)
7.4.1 How will the pattern on the screen change if red light, with a wavelength of 660 nm, is used instead of green light? (2)
7.4.2 Explain the answer to QUESTION 7.4.1. (1)
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