Concepts Of Physics MCQ Edition [Volume 1]PhysicsGeometrical Optics
To account for the effect of the lens thickness t , four modifications to the lens formula are proposed. Which of these is most likely correct?
Options
- A1 v - t - 1 u + t = 1 f
- B1 v - 1 u = t uf
- Ct v^2 - 1 u = 1 f
- D1 v - 1 u + t uv = t f
Correct answer
A. 1 v - t - 1 u + t = 1 f
Step-by-step solution
For a modified lens formula to be correct, it must reduce to the standard thin lens formula when the thickness of the lens approaches zero ( t 0 ). The standard thin lens formula is given by: 1 v - 1 u = 1 f Substituting t = 0 into the first expression gives 1 v - 0 - 1 u + 0 = 1 v - 1 u = 1 f , which matches the standard formula. Substituting t = 0 into the second expression gives 1 v - 1 u = 0 , which is incorrect. Substituting t = 0 into the third expression gives - 1 u = 1 f , which is incorrect. Substituting t