Light (Cambridge O Level Physics)

Fig. 6.1 represents the electromagnetic spectrum.

State the radiation in each of the regions represented by A, B, C and D in Fig. 6.1.

A source emits visible light.

Fig. 6.2 shows a ray of red light from the source incident on the face XY of a glass prism at point S. 

The angle of incidence i of the ray is 35 °. The refractive index of the glass for red light is 1.5.

Fig. 7.1 shows red light travelling from air into a prism made of diamond. The path of the red light is incomplete.

The refractive index of diamond is 2.42.

Calculate angle x.

angle x = .........................................................

Explain the term total internal reflection.

The angle y is greater than the critical angle of diamond.

 
On Fig. 7.1, draw the path of the red light through and out of the prism after point A.

Fig. 7.1 shows a ray of light in water that is incident on a submerged, transparent plastic block.

State what happens to the speed of light as it enters the plastic block. Explain your answer.

Fig. 7.2 shows the two principal focuses F₁ and F₂ of a thin converging lens.

Fig. 7.2 also shows an object O of height 1.2cm placed close to the lens. Two rays from the tip of the object O are incident on the lens.

Fig. 7.1 shows a ray of light striking a plane mirror at point P.

Fig. 7.2 shows an object OB positioned 20cm from a thin converging lens. Both principal focuses of the lens are labelled F.

Two rays from the tip B of the object are incident on the lens, as shown in Fig. 7.2.

On Fig. 7.2, continue the paths of these two rays to show the position of the image of OB formed by the lens. Draw an arrow to show the size, position and orientation of the image of OB.

Fig. 6.1 shows a ray of red light incident on part of a lens.

Fig. 6.2 shows two parallel rays of light travelling towards another lens.

The two rays of light pass through the lens to form an image.

 
On Fig. 6.2, continue the path of the rays. Extend the rays for at least 5 cm beyond the lens.

A ray of light in air is incident on a glass block. The light changes direction.

State

Fig. 5.1 shows a thin converging lens of focal length 3.5cm.

Fig. 5.1 shows a visible spectrum focused on a screen by passing light from a source of white light through a lens and a prism.

Extended

Fig. 5.2 shows a section of an optical fibre in air. A ray of light is incident on the fibre wall at X.

Fig. 7.1 shows a converging lens and the image I formed when an object is placed to the left of the lens. The principal focuses are labelled A and B and the centre of the lens is labelled C.

                                                   

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Fig. 7.2 shows green light passing through a triangular glass block.

Red light enters the triangular glass block shown in Fig. 7.2 along the same path as the green light.

  

  

On Fig 7.3 draw the path of the red light within the rectangular glass block.

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Fig. 6.2 shows three rays of red light each entering a semi-circular glass block.

Using the information in Table 6.1, draw on Fig. 6.2 to complete the path of each ray of red light.

Fig. 6.1 shows an arrangement of glass prisms inside a box. The angles of the prisms are 45°, 45° and 90°.

This is a device used to view objects that are behind a wall.
The incident ray of light undergoes total internal reflection in the prisms.

 
On Fig. 6.1, complete the path of the ray through the device and show the ray as it emerges from the box.

Show that the refractive index of glass with a critical angle of 45° is 1.41.

Which distance is the focal length of the lens? Tick one box.

  C to F₁ 

 O to C

 F₂ to I

 O to I

On Fig. 8.1, extend the two rays from the arrowhead on the object until both reach the position of the image.

The object is moved a small distance away from the lens. State the effect, if any, this has on the position and size of the image.

State the term used for the dashed lines drawn in Fig. 8.1.

Use Fig. 8.1 to identify the three angles in the list. Place the correct letter in the box to indicate each angle.

 angle of incidence

 angle of reflection

 angle of refraction

The ray of light in Fig. 8.1 changes direction as it enters the glass block. State the name of this effect and explain why it happens.

Fig. 5.1 shows part of the ray diagram of a lens being used as a magnifying glass. 

Three rays are shown coming from the top of an object O.

The points labelled F are one focal length from the lens. 

Fig. 5.1

State the name of the type of lens shown in Fig. 5.1.

Describe what happens to the ray of light R:

• as it enters the lens ...........................................................................

• as it leaves the lens. ..........................................................................

Using all three rays from O, complete Fig. 5.1 to show the image formed.

Underline all of the words in the list that describe the image formed in (c).

inverted       upright       real       virtual

Fig. 5.1 shows light in air, incident on the side of a rectangular glass block at an angle of 60°.

Fig. 5.1

The refractive index of the glass is 1.6. The light travels in the glass and is incident on side XY at P.

Underline all the terms that describe a wave of light.

    electromagnetic    longitudinal    radioactive   transverse

At the point where the light enters the glass, the angle of refraction is r.

Calculate angle r.

r = ........................................................ °

c = ........................................................ ° [2]
 

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