Amplitude of an electromagnetic wave is equal to ?

Options

A. `E_0 =cB_0`
B. `E_0 =c//B_0`
C. `E_0 =c - B_0`
D. `E_0=c+B_0`

Explanation

To find the amplitude of an electromagnetic wave, we start by understanding the relationship between the electric field and the magnetic field in an electromagnetic wave.

### Step-by-Step Solution:

1. **Understand the Definitions**:
- The amplitude of the electric field is denoted as \( a_0 \).
- The amplitude of the magnetic field is denoted as \( b_0 \).

2. **Recall the Equations**:
- The electric field of an electromagnetic wave can be expressed as:
\[ E = a_0 \sin(kx - \omega t) \]
- The magnetic field can be expressed as:
\[ B = b_0 \sin(kx - \omega t) \]

3. **Identify the Relationship**:
- The amplitudes of the electric and magnetic fields are related by the equation:
\[ a_0 = c \cdot b_0 \]
- Here, \( c \) is the speed of light in vacuum.

4. **Select the Correct Option**:
- From the given options:
- Option 1: \( a_0 = c b_0 \) (Correct)
- Option 2: \( a_0 = \frac{c}{b_0} \) (Incorrect)
- Option 3: \( a_0 = c - b_0 \) (Incorrect)
- Option 4: \( a_0 = c + b_0 \) (Incorrect)

5. **Conclusion**:
- The amplitude of an electromagnetic wave is equal to \( a_0 = c b_0 \).