Sec 4 Combined Science (Physics) Light topical questions

State the law of reflection.

A ray strikes a plane mirror at 40° to the normal. State the angle of reflection and sketch the rays’ arrangement about the normal.

Light passes from air into water. State whether it bends towards or away from the normal, and whether it slows down or speeds up.

State what is meant by the focal length of a converging lens.

For light crossing from air into glass: i = 20° gives r = 13.2°, and i = 30° gives r = 19.5°. Show that sin i ÷ sin r is constant and state the value for these media.

Light travels at 3 × 10⁸ m/s in vacuum and 2.25 × 10⁸ m/s in water. Calculate the refractive index of water.

Using n = 1.5 for glass, calculate the angle of refraction when the angle of incidence is 45°.

A straw standing in a glass of water looks bent at the water surface. Name the effect and explain it using refraction.

Light crosses from air into a medium at i = 50° and is measured refracting at r = 30°. (a) Calculate the refractive index. (b) Calculate the speed of light in the medium. (c) State how the bend changes if the ray enters a medium of higher n at the same angle.

Describe the image formed by a converging lens when the object is (a) beyond 2F, (b) between F and 2F, (c) inside F. State a device that uses each arrangement.

A student measures angles for light entering a transparent block: i = 40°, r = 25.4°. (a) Calculate the block’s refractive index. (b) Calculate the speed of light inside it. (c) The student repeats with i = 55° and predicts r = 40°. Check the prediction using the refractive index.

A camera and a magnifying glass both use converging lenses. For each, state where the object sits relative to F and 2F, describe the image, and explain why that image suits the device.