A plane `E.M.` wave of frequency `40 MHz` travels along `X`-axis. At same point at same instant, the electric field `E` has maximum value of `750 N//C` in `Y`- direction. The magnitude and direction of magnetic field is

Explanation

To solve the problem, we need to determine the magnitude and direction of the magnetic field associated with a plane electromagnetic wave traveling along the x-axis, given the electric field's characteristics.

### Step-by-Step Solution:

1. **Identify the Given Information:**
- Frequency of the electromagnetic wave, \( f = 40 \, \text{MHz} = 40 \times 10^6 \, \text{Hz} \)
- Maximum value of the electric field, \( E_0 = 750 \, \text{N/C} \)
- Direction of the electric field, \( \vec{E} \) is along the y-axis.
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