12 Light – 2021 J

The diagram shows a narrow beam of light incident on a glass-air boundary. Some of the light emerges along the surface of the glass and some is reflected back into the glass.

Is this an example of total internal reflection? Is the angle θ is the critical angle?

• No, yes

• No, no

• Yes, no

• Yes, yes

An object is placed in front of a thin converging lens.

The diagram shows the paths of two rays from the top of the object. An image of the object is formed on a screen to the right of the lens. How does this image compare with the object?

• It is larger and inverted.

• It is larger and the same way up.

• It is smaller and inverted.

• It is smaller and the same way up.

Which statement about the image of an object formed in a plane mirror is correct?

• It is smaller than the object.

• It is the same size as the object.

• It is larger than the object.

• It is inverted.

The table shows information about different colours of light.

Using the data, what is the frequency of orange light?

• 4.0 x 10¹⁴ Hz

• 5.0 x 10¹⁴ Hz

• 6.0 x 10¹⁴ Hz

• 7.0 x 10¹⁴ Hz

The diagram shows a ray of light striking a plane mirror. Through which point does the reflected ray pass?

Light travelling at a speed of 3.0 × 10⁸ m/s strikes the surface of a glass block and undergoes refraction as it enters the block.

The diagram shows a ray of this light before and after it enters the block.

What is the speed of light in the glass?

• 1.8 × 10⁸ m/s

• 4.5 × 10⁸ m/s

• 5.0 × 10⁸ m/s

A beam of light is monochromatic.

What does monochromatic mean?

• All the waves in the beam must have the same frequency only.

• All the waves in the beam must have the same amplitude only.

• All the waves in the beam must have the same speed only.

• All the waves in the beam must have the same amplitude, frequency and speed.

What causes the change in direction when light travels from air into glass?

• The amplitude of the light changes.

• The colour of the light changes.

• The frequency of the light changes.

• The speed of the light changes.

Light from a torch is incident on a plane mirror. The angle of incidence is 38°. What is the angle of reflection?

• 38°

• 52°

• 76°

• 142°

A thin converging lens is used to produce a sharp image of a candle. Various sharp images are produced on the screen by moving the lens and the screen backwards and forwards.

Which statement is always correct?

• The image is at the principal focus (focal point) of the lens.

• The image is bigger than the object.

• The image is closer to the lens than the object.

• The image is inverted.