IGCSE Physics (0625) 3.2.1 Reflection of light Paper 3

Question

Fig. 6.1 shows the path of a ray of red light through a glass block in air.
The critical angle for the red light as it travels from glass into air is 43°.

(a) (i) On Fig. 6.1, label the angle of incidence at A. Use the letter X to label the angle.
(ii) State the name of the process which occurs at A.
(iii) State the name given to the dashed line at A.

(b) (i) On Fig. 6.1, one of the angles at B is 62°. State the value of the angle labelled P.
(ii) State the name of the process which occurs at B.

(c) On Fig. 6.1, draw the path of the ray of red light as it travels from C into the air.

Answer/Explanation

Answer:

(a) (i) angle of incidence correctly identified (with × between normal and incident ray) 
(ii) refraction
(iii) normal(line)

(b) (i) 62° 
(ii) reflection
total refracted away from normal

(c) ray refracted away from normal

Question

(a) Fig. 9.1 shows two rays of light X and Y leaving an object O. The rays strike a plane mirror. Ray X is reflected as shown.

(i) On Fig. 9.1, draw the normal at the point where ray X strikes the mirror.

(ii) On Fig. 9.1, draw the path of ray Y after it strikes the mirror.

(b) An object O is placed on the left of a thin converging lens. F is the principal focus.

This arrangement is shown in Fig. 9.2.

                 

Two rays from the top of the object are incident on the lens, as shown in Fig. 9.2.

On Fig. 9.2, draw the path of each ray to locate the position of the image of O formed by the lens.

On Fig. 9.2, draw an arrow to represent the image and label it I.

Answer/Explanation

Answer:
(a)
(i)
normal at X correct by eye
(ii) reflected ray for Y has angle r by eye

(b) horizontal ray drawn to continue through F
ray to centre drawn to continue undeviated
image drawn correctly where rays cross

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