In case of linearly polarised light, the magnitude of the electric field vector

Options

A. is parallel to the direction of propagation
B. does not change with time
C. increases linearly with time
D. varies perodically with time

Explanation

To solve the question regarding the magnitude of the electric field vector in the case of linearly polarized light, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Polarization**:
- Polarization is a phenomenon that restricts the vibrations of the electric field vector of light waves to a particular direction. In the case of linearly polarized light, the electric field oscillates in a single plane.

**Hint**: Remember that polarization affects the direction of the electric field vector.

2. **Electric Field Vector in Electromagnetic Waves**:
- Light can be described as an electromagnetic wave, which consists of oscillating electric and magnetic fields. The electric field vector (E) varies with time and space.

**Hint**: Recall that electromagnetic waves consist of both electric and magnetic fields that oscillate perpendicular to each other.

3. **Variation of the Electric Field Vector**:
- For linearly polarized light, the electric field vector can be expressed mathematically as:
\[ E(t) = E_0 \sin(\omega t + \phi) \]
where \(E_0\) is the maximum amplitude, \(\omega\) is the angular frequency, \(t\) is time, and \(\phi\) is the phase constant. This equation shows that the electric field varies sinusoidally with time.

**Hint**: Consider how the sine function represents periodic motion.

4. **Conclusion on the Magnitude of the Electric Field Vector**:
- Since the electric field vector varies sinusoidally with time, we conclude that the magnitude of the electric field vector in linearly polarized light varies periodically.

**Hint**: Think about how periodic functions repeat their values at regular intervals.

5. **Final Answer**:
- The correct answer is that the magnitude of the electric field vector varies periodically with respect to time.

### Summary:
The electric field vector of linearly polarized light oscillates in a single direction and varies periodically over time, reflecting the nature of electromagnetic waves.