12 Light – 2019 June

An object is placed 30 cm in front of a plane mirror. Which statement describes the image of the object?

• The image is the same size and 30 cm from the object.

• The image is the same size and 60 cm from the object.

• The image is smaller and 30 cm from the object.

• The image is smaller and 60 cm from the object.

The diagram shows light incident at a glass-air boundary. The angle of incidence i of the ray is greater than the critical angle.

Which line shows the path of the light after it meets the boundary?

The diagram shows radiation from a lamp passing through a prism. Which type of radiation is found at P?

• γ-rays

• infrared

• ultraviolet

• X-rays

Which conditions are necessary for light to be totally internally reflected?

• the incident light is in the less dense medium and the angle of incidence is less than the critical angle

• the incident light is in the less dense medium and the angle of incidence is greater than the critical angle

• the incident light is in the more dense medium and the angle of incidence is less than the critical angle

• the incident light is in the more dense medium and the angle of incidence is greater than the critical angle

Which diagram shows the dispersion of white light by a glass prism?

• 
• 
• 
• 

A student draws a ray diagram to show how a ray of light is reflected by a number of mirrors. Which reflection has not been drawn correctly? .........

Light passes through a glass block. What is the path of the light? ......

A small object O is placed near a converging lens, as shown. The lens forms an image I. Which statement is correct?

• The image I is diminished.

• The image I is inverted.

• The image I is real.

• The object O is closer to the lens than its principal focus.

Light is travelling through air. The light strikes a glass block at an angle of incidence of 45°. The glass has a refractive index of 1.4. What is the angle of refraction of the light as it enters the glass?

• 29°

• 30°

• 32°

• 82°

A beam of light passes through a vacuum and then enters a liquid. The diagram shows the path it takes. The light travels through the vacuum at a speed of 3.0 × 10⁸ m/s.

What is the speed of light in the liquid?

• 1.9 × 10⁸ m/s

• 4.6 × 10⁸ m/s

• 4.8 × 10⁸ m/s