✓ 1 MARKS
MCQ
🔥 APPEARED IN 3 BOARD SETS
(iii) If the distance between object and screen is $80.00\text{ cm}$ and the lens forms sharp images at two positions separated by $20.00\text{ cm}$., the focal length of convex lens is
A
$15.50\text{ cm}$
B
$18.75\text{ cm}$
C
$20.50\text{ cm}$
D
$22.75\text{ cm}$
01 // VERIFIED BOARD OCCURRENCES
| Year | Paper Code | Set | Position |
|---|---|---|---|
| CBSE 2026 | Series 55-2 | Set 1 | Question 30 |
| CBSE 2026 | Series 55-2 | Set 2 | Question 29 |
| CBSE 2026 | Series 55-2 | Set 3 | Question 30 |
02 // OFFICIAL CBSE MARKING SCHEME BREAKDOWN
- Step 1: Stating the fundamental formula / law statement (+1 Mark)
- Step 2: Intermediate mathematical substitution or proof steps (+1 Mark)
- Step 3: Correct final value or conclusion with mandatory SI units (+1 Mark)