2008 Question 9
(i) What is meant by refraction of light?
(ii) State Snell’s law of refraction.
(iii)An eye contains a lens system and a retina, which is 2.0 cm from the lens
system. The lens system consists of the cornea, which acts as a fixed lens of
power 38 m–1, and a variable internal lens just behind the cornea.
The maximum power of the eye is 64 m–1.
Calculate how near an object can be placed in front of the eye and still be in
(iv) Calculate the maximum power of the internal lens.
(v) Light is refracted as it enters the cornea from air as shown in the diagram.
Calculate the refractive index of the cornea.
(vi) Draw a diagram to show the path of a ray of light as it passes from water of refractive index
1.33 into the cornea.
A swimmer cannot see properly when she opens her eyes underwater.
(vii) Why does the cornea not act as a lens?
(viii) What is the maximum power of the eye?
(ix) Why do objects appear blurred?
(x) Explain how wearing goggles allows objects to be seen clearly.
2008 Question12 (b)
(i) The pitch of a musical note depends on its frequency.
(ii) On what does (i) the quality, (ii) the loudness, of a musical note depend?
(iii)What is the Doppler Effect?
(iv) A rally car travelling at 55 m s–1 approaches a stationary observer. As the car passes, its
engine is emitting a note with a pitch of 1520 Hz. What is the change in pitch observed as the
car moves away?
(v) Give an application of the Doppler Effect.