Optics Practice Questions

State the law of reflection.

The incident ray makes an angle of $32°$ with the surface of the mirror.

State the angle of reflection.

angle of reflection = .............................................. $°$

You can see a clear image of your face in the mirror, but not in a sheet of white paper.

Explain why.

Explain, in terms of what happens to light at the surface of the jumper, why the jumper looks green.

The shop then lights the window with red light only.

State the colour the jumper appears to be and explain your answer.

State which lens, A, B or C, is a diverging lens.

Lens A and lens B are made from the same type of glass.

State which of these two lenses has the greater power and explain your answer.

Describe a method the student could use to obtain the measurements needed.

Explain why the student should use a ray of light that is as narrow as possible.

On Figure 3, mark the angle of incidence with the letter $i$ and draw the path of the ray inside the glass block.

Explain, in terms of the speed of light, why the ray changes direction as it enters the glass.

Explain what happens to the white light when it passes through a green filter.

A green filter and a red filter are placed one behind the other in front of a white stage light.

Explain what is seen on a white screen in front of the light.

A converging lens has a power of $8.0$ dioptres.

Calculate the focal length of this lens in cm.

focal length = .............................................. cm

A small insect is placed $6.0$ cm from this lens and viewed through the lens.

Describe the image that is seen.

State what is meant by the critical angle.

A ray of light travelling inside the glass meets the glass–air boundary at an angle of $55°$ to the normal.

Describe what happens to this ray. Give a reason for your answer.

Explain how light is able to travel along a curved optical fibre.

Calculate the value of

$$\dfrac{\text{angle of refraction}}{\text{angle of incidence}}$$

for an angle of incidence of $20°$ and for an angle of incidence of $60°$. Give each answer to 2 significant figures.

The student concludes that the angle of refraction is directly proportional to the angle of incidence.

Use the results to explain whether the data support this conclusion.

Suggest two improvements the student could make to the investigation to increase confidence in the conclusion.

Explain, in terms of the speed of light in glass, why the white light is split into a spectrum.

Violet light is deviated more than red light by the prism.

State what this tells you about the speed of violet light in the glass.

The prism is replaced by a rectangular glass block and the white light is directed at one face at the same angle. A spectrum is not seen in the light leaving the block.

Explain why.

On Figure 5, complete the ray diagram to find the position of the image.

Describe the image formed by the lens in Figure 5.

The converging lens is replaced by a diverging lens, with the object in the same position.

State one way in which the image formed is different.