The amplitudes of electric and magnetic field increases by a factor of 2 each then velocity of light:

Options

A. decreases
B. remains constant
C. increases thrice
D. increases twice

Answer

To solve the problem, we need to analyze the relationship between the amplitudes of the electric and magnetic fields in an electromagnetic wave and the speed of light.

### Step-by-Step Solution:

1. **Understanding Electromagnetic Waves**:
- Electromagnetic waves consist of oscillating electric (E) and magnetic (B) fields that are perpendicular to each other and to the direction of wave propagation.

2. **Amplitude Increase**:
- In this problem, both the electric field amplitude (E) and the magnetic field amplitude (B) are increased by a factor of 2. This means:
- New Electric Field Amplitude, \( E' = 2E \)
- New Magnetic Field Amplitude, \( B' = 2B \)

3. **Speed of Light Formula**:
- The speed of light (c) in a vacuum is given by the equation:
\[ c = \nu \lambda \]
where \( \nu \) is the frequency and \( \lambda \) is the wavelength.

4. **Frequency and Wavelength**:
- The frequency \( \nu \) of the wave remains constant because the increase in amplitude does not affect the frequency of the oscillations.
- The wavelength \( \lambda \) also remains constant for the same reason.

5. **Impact on Speed of Light**:
- Since both frequency and wavelength are unchanged, we can conclude that the speed of light \( c \) remains constant.
- Therefore, even though the amplitudes of the electric and magnetic fields have increased, the speed of light does not change.

### Conclusion:
The velocity of light remains constant despite the increase in the amplitudes of the electric and magnetic fields.