Light enters a parallel-sided glass block at A. The angle between the side of the block and the ray of light in air is 35°. The light then strikes the edge of the block at B. Fig. 7.1 shows the ray of light and the glass block. [Figure 7.1] The angle of refraction in the glass at A is 33°.

1. (a)Calculate the refractive index for light in the glass. refractive index =[2]
2. (b)(i)The light undergoes total internal reflection at B. State one condition necessary for total internal reflection to occur.[1]
3. (b)(ii)On Fig. 7.1, continue the ray to show the path of the light after total internal reflection at B and until it leaves the block.[1]

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