Magnetic field in an electromagnetic wave has maximum value of 20 nT. Then what will be the maximum value of electric field strength?

Options

A. `9 V m ^(-1)`
B. `12 V m ^(-1)`
C. `3 V m ^(-1)`
D. `6 V m^(-1)`

Explanation

To find the maximum value of the electric field strength (E_max) in an electromagnetic wave given the maximum value of the magnetic field (B_max), we can use the relationship between the electric field and the magnetic field in electromagnetic waves.

### Step-by-Step Solution:

1. **Identify the Given Data**:
- Maximum magnetic field (B_max) = 20 nT = 20 × 10^(-9) T.

2. **Use the Relationship between Electric Field and Magnetic Field**:
- The relationship between the maximum electric field (E_max) and the maximum magnetic field (B_max) in an electromagnetic wave is given by:
\[ E_{\text{max}} = c \cdot B_{\text{max}} \]
where \( c \) is the speed of light in vacuum, approximately \( 3 \times 10^8 \) m/s.

3. **Substitute the Values**:
- Substitute the values of \( B_{\text{max}} \) and \( c \) into the equation:
\[ E_{\text{max}} = (3 \times 10^8 \, \text{m/s}) \cdot (20 \times 10^{-9} \, \text{T}) \]

4. **Calculate the Electric Field**:
- Perform the multiplication:
\[ E_{\text{max}} = 3 \times 20 \times 10^8 \times 10^{-9} = 60 \times 10^{-1} \, \text{V/m} \]
- Simplifying gives:
\[ E_{\text{max}} = 6 \, \text{V/m} \]

5. **Final Answer**:
- The maximum value of the electric field strength is **6 V/m**.