Physics 2 · Unit 5 · Paper 3

Geometric Optics unit test

A test on this unit alone, marked as a percentage and a letter grade — for the test your class is actually sitting, rather than for May. Answer everything, then submit once: seeing the answer to question 3 before attempting question 4 makes the final percentage meaningless.

Paper 1 Paper 2 Paper 3

Each paper is built from this unit’s 20 terms and is the same for everyone, so a teacher can assign “Unit 5, Paper 3” and every student sits the identical test. Multiple choice is marked objectively; the written sections you mark yourself against the model answer and rubric.

Suggested time 37 min 34 points0/17 attempted

Converging vs diverging lens

Predicting image type without calculating

Why the image of a half-covered lens is dimmer, not halved

Ray diagram rules for a lens

Apparent depth

Index of refraction

Fiber optics

Real image on a screen

Concave mirror

Magnification

Why a magnifying glass must be held close

Real vs virtual images

Short answer 1. Define or explain: Law of reflection

3 pts

Short answer 2. Define or explain: Thin lens equation

3 pts

Short answer 3. Define or explain: Sign conventions for lenses and mirrors

3 pts

Short answer 4. Define or explain: Total internal reflection

3 pts

Free response

10 pts

A converging lens has a focal length of 12 cm. An object 4.0 cm tall is placed 18 cm from the lens on the principal axis. (a) Calculate the image distance and the image height, and state whether the image is real or virtual and upright or inverted. (b) Describe the principal rays you would draw to locate this image. (c) The object is now moved to 6.0 cm from the lens. Calculate the new image distance and magnification, and describe the image. (d) Explain, using your results, how a converging lens is used as a magnifying glass. (e) A student covers the lower half of the lens with tape. Predict the effect on the image formed in part (a) and justify your prediction.