Free Optics MCQs with Answers
21 Optics MCQs from Physics, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
21 questions · page 3 of 3
21. For a lens, the relationship between object distance, image distance and focal length is
- A. 1 over f equals 1 over v plus 1 over u, with a sign convention applied
- B. f equals u plus v
- C. f equals uv
- D. 1 over f equals u plus v
Explanation: The lens formula relates the reciprocals rather than the quantities themselves, and a consistent sign convention is essential, with real distances and real images taken as positive in the usual convention. Magnification is the image distance divided by the object distance. Careless sign handling is the commonest source of wrong answers in lens problems.
Correct answer: 1 over f equals 1 over v plus 1 over u, with a sign convention applied