✓ 1 MARKS
MCQ
🔥 APPEARED IN 3 BOARD SETS
The magnetic field in a plane electromagnetic wave travelling in glass ($n = 1\cdot 5$) is given by
$B_y = (2 \times 10^{-7}\text{ T}) \sin (\alpha x + 1\cdot 5 \times 10^{11} t)$
where $x$ is in metres and $t$ is in seconds. The value of $\alpha$ is :
A
$0\cdot 5 \times 10^3\text{ m}^{-1}$
B
$6\cdot 0 \times 10^2\text{ m}^{-1}$
C
$7\cdot 5 \times 10^2\text{ m}^{-1}$
D
$1\cdot 5 \times 10^3\text{ m}^{-1}$
01 // VERIFIED BOARD OCCURRENCES
| Year | Paper Code | Set | Position |
|---|---|---|---|
| CBSE 2026 | Series 55-5 | Set 1 | Question 6 |
| CBSE 2026 | Series 55-5 | Set 2 | Question 11 |
| CBSE 2026 | Series 55-5 | Set 3 | Question 4 |
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)