✓ 3 MARKS
Derivations
🔥 APPEARED IN 3 BOARD SETS
(a) When a parallel beam of light enters water surface obliquely at some angle, what is the effect on the width of the beam ?
(b) With the help of a ray diagram, show that a straw appears bent when it is partly dipped in water and explain it.
(c) Explain the transmission of optical signal through an optical fibre by a diagram.
01 // VERIFIED BOARD OCCURRENCES
| Year | Paper Code | Set | Position |
|---|---|---|---|
| CBSE 2025 | Series 55-2 | Set 1 | Question 26 |
| CBSE 2025 | Series 55-2 | Set 2 | Question 23 |
| CBSE 2025 | Series 55-2 | Set 3 | Question 28 |
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)