Problems: Reflection, Refraction and Diffraction

Question 1

(a) Explain what is meant by

(i) a compression,

(ii) a rarefaction,

(iii) a longitudinal wave,

(iv) a transverse wave.

(b) A ship sends out a sound wave and receives an echo after 1 second. If the speed of sound in water is 1500 m/s, how deep is the water?.

(c) Explain  with diagrams, what is meant by

(i) amplitude,

(ii) wavelength,

(iii) freequency

Question 2

Copy out and complete:

The law of reflection states that the angle of _________ is always _______ to the angle of incidence.

Both angles are measured relative to the _________, a line that is at _______ degrees to the reflecting surface at the point of reflection.

A plane mirror forms a _______ image which is unlike a _____ image in that it cannot be cast onto a screen. The image in a plane mirror is also the same ______ and the same way up as the object.


Question 3

The figure below shows a rectangular glass block ABCD.


(a) The ray FE is partly reflected and partly refracted at E.

      (i) On Figure, draw in the approximate path of the refracted ray, within and beyond the block. Label the ray refracted ray.

      (ii) On Figure, draw in the path of the reflected ray. Label the ray reflected ray.

(b) A second ray, almost parallel to AE, strikes the block at E and is partly refracted at an angle of refraction of 43°.

       (i) State an approximate value for the angle of incidence at E.

        (ii) State an approximate value for the critical angle for the light in the glass block.

       (iii) Calculate an approximate value for the refractive index of the glass of the block.

(c) The speed of the light along ray FE is 3.0 x 108 m/s. Calculate the speed of the refracted light in the glass block.

Question 4

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Refraction occurs when a wave changes ______ as it crosses the boundary between two regions. The _________ of the wave also usually changes.

Light rays deviate ________ the normal when they pass from less dense air to more dense _________. The greater the angle of incidence the greater is the _________.

Different ______ of light deviate by different amounts. Violet deviates the _____. A prism can be used to split the colours of white light into a spectrum. This is called _________.

Question 5

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White light is composed of ________ colors, in order: red ________, ________, ________, ________, ________, ________, which form the visible _________. The color with the longest wavelength is _______. The color deviated through the largest angle by a prism is ________.

The full electromagnetic spectrum, in order, is: gamma rays, _____, _____, _____,  ____, ____. The section with the longest wave length is _______.