Physics Circle home Student Login

Home›Chapters›Ray Optics PYQs›Combination of Lenses›Question 36

JEE Main 2023 (12 Apr, Shift 1) · Combination of Lenses

Combination of Lenses question from JEE Main 2023 (12 Apr, Shift 1)

Q36JEE Main 2023 · 12 APR · SHIFT 1Medium

Combination of Lenses

Two convex lenses of focal length 20 cm20\text{ cm} each are placed coaxially with a separation of 60 cm60\text{ cm} between them. The image of the distant object formed by the combination is at _____________ cm\text{cm} from the first lens.

Numerical answer type. Work it out, then open the answer.

Show answer and solution

Answer: 100

  1. First lens images the distant object at its focus, 20 cm behind it.
  2. Second lens: object 60−20=40 cm60 - 20 = 40\text{ cm} away, u=−40u = -40, f=20f = 20: 1v=120−140⇒v=40 cm\frac{1}{v} = \frac{1}{20} - \frac{1}{40} \Rightarrow v = 40\text{ cm}.
  3. Distance from first lens =60+40=100 cm= 60 + 40 = 100\text{ cm}
Report a mistake

More questions on Combination of Lenses