GCSE Physics Light and lenses questions by topic

Complete the sentences about light. (Physics only)

1. (a)A convex lens … parallel rays to a focus.[1]
2. (b)The distance from the lens centre to the principal focus is the …[1]
3. (c)Magnification = image height ÷ …[1]
4. (d)Angles of incidence and reflection are measured from the …[1]

A slide 3.0 cm tall is projected so its image on a screen is 12 cm tall. (Physics only)

1. (a)Write down the equation for magnification.[1]
2. (b)Calculate the magnification.[2]
3. (c)State whether the projected image is real or virtual, and how you know.[1]

A blue book is lit by a torch covered with a red filter. (Physics only)

1. (a)State what colour light the filter allows through.[1]
2. (b)State what happens to the other colours in the white light.[1]
3. (c)Explain what colour the book appears, and why.[2]

A student sees a virtual image in a mirror and a real image on a screen. (Physics only)

1. (a)State the difference between a real image and a virtual image.[2]
2. (b)Give one everyday example of each.[2]

A magnifying glass produces an image magnified 2.5 times; the image of a printed letter is 7.5 mm tall. (Physics only)

1. (a)Calculate the height of the actual letter.[2]
2. (b)Describe the image (three properties).[3]

An object stands far beyond twice the focal length of a convex lens. (Physics only)

1. (a)Describe the image formed (position, three properties).[4]
2. (b)Name a device that uses the lens in exactly this arrangement.[2]

A student investigates reflection with a ray box, a plane mirror and a protractor sheet. (Physics only)

1. (a)Describe how to measure the angles needed to test the law of reflection.[3]
2. (b)State the expected result.[1]
3. (c)The mirror is replaced by a sheet of crumpled foil. Describe and explain the change.[2]

White light passes through a cyan filter and then a yellow filter. (Physics only)

1. (a)State which colour(s) the cyan filter transmits.[1]
2. (b)Explain the colour that finally emerges from the two filters.[3]
3. (c)State one change that would make the emerging beam brighter.[1]

A student uses a Leslie cube filled with water at 85 °C to compare infrared emission from matte black, glossy black, matte white and polished silver faces. (Physics only)

1. (a)Describe how to obtain a fair comparison of the four faces.[3]
2. (b)State the expected order of infrared intensity, strongest to weakest.[2]
3. (c)Explain why this practical also tells us about absorption.[2]

A jeweller’s magnifying glass has focal length 6.0 cm. A gem is held 4.0 cm from the lens (inside the focal length). (Higher, Physics only)

1. (a)Describe the image the jeweller sees and where it forms.[4]
2. (b)Explain why the same lens held 12 cm from the gem could not be used to view it this way.[3]
3. (c)State whether magnification has a unit and justify your answer.[1]

A student compares refraction through a rectangular glass block and a shallow water tray, measuring the angle of refraction for a 40° angle of incidence each time. The glass gives 25°, the water 29°. (Higher, Physics only)

1. (a)Explain why both refracted angles are smaller than 40°.[3]
2. (b)Explain what the different angles show about glass and water.[2]
3. (c)State two control variables for a fair comparison.[2]

A dark-roofed house and a white-roofed house stand side by side in summer sunshine. (Higher, Physics only)

1. (a)Explain, using absorption and emission of radiation, why the dark roof gets hotter.[3]
2. (b)Explain what happens to the temperature of each roof as evening falls and the sunshine stops.[3]
3. (c)Give one advantage of a white roof besides comfort.[2]