1. 1
   A magazine photographer uses a camera fitted with a thin converging (convex) lens to bring parallel rays of light from a very distant mountain to a sharp focus on the camera's sensor.

   (a)

   What is the specific name given to the point where these parallel rays converge?

   [1 mark]

   • AThe principal focus (focal point)
   • BThe critical point
   • CThe centre of curvature
   • DThe normal

   (b)

   What term describes the distance from the centre of the converging lens to the point where the parallel rays from the mountain converge?

   [1 mark]

   • AThe critical angle
   • BThe wavelength
   • CThe amplitude
   • DThe focal length

   (c)

   Describe the characteristics of the image of the distant mountain formed on the camera sensor, using the terms real/virtual, upright/inverted and enlarged/diminished/same size.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   An optician examines a patient using a thin converging lens, holding it close to a page of small text, closer to the page than the lens's focal length, so that the patient can use it as a magnifying glass.

   (a)

   What type of image is formed when a converging lens is used this way, as a magnifying glass?

   [1 mark]

   • AA real, inverted, diminished image
   • BA virtual, upright, enlarged image
   • CA real, upright, same-size image
   • DA virtual, inverted, diminished image

   (b)

   The optician also demonstrates a thin diverging (concave) lens to explain how it forms images differently from a converging lens. A diverging lens acting on an object always produces which type of image, regardless of the object's distance from the lens?

   [1 mark]

   • AA real, upright, diminished image
   • BA real, inverted, enlarged image
   • CA virtual, upright, diminished image
   • DA virtual, inverted, enlarged image

   (c)

   Explain the difference between a real image and a virtual image, and state which type of image is formed when the converging lens is used as a magnifying glass in this way.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   An optician explains that a patient with long-sightedness struggles to focus clearly on nearby objects, because the patient's eye brings light from near objects to a focus behind the retina rather than exactly on it.

   (a)

   (a) State which type of lens, converging or diverging, is used in spectacles to correct long-sightedness, and explain why this type of lens helps.

   [3 marks]

   (b)

   A second patient is short-sighted, and their eye brings light from distant objects to a focus in front of the retina rather than exactly on it. Explain fully which type of lens should be used to correct this condition, describing how the lens changes the path of the light rays before they enter the eye, and contrast this with the correction described for the long-sighted patient in part (a).

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A photographer sets up a converging lens with a fixed focal length in front of a small illuminated object, and moves the object slowly from a position far beyond twice the focal length, gradually towards the lens.

   (a)

   Explain fully, using the properties of converging lenses, how the position, size and nature (real/virtual) of the image changes as the object is moved from far beyond twice the focal length, to exactly at twice the focal length, then to between the focal length and twice the focal length, and finally to exactly at the focal length itself.

   [6 marks]

   (b)

   The photographer then continues moving the same illuminated object even closer to the lens, from exactly at the focal length to a position between the lens and the focal length. Explain fully what happens to the nature, position and size of the image in this final range, and explain overall why this behaviour, together with your answer to part (a), demonstrates that a single converging lens can act either as a camera lens or as a magnifying glass, depending on the position of the object relative to the focal length.

   [6 marks]

   Total for question 4: 12 marks

End of questions