A : In an EM wave the magnitude of the electric field vector is more than the magnitude of the magnetic field vector.
R : Energy of the EM wave is shared equally between the electric and magnetic fields.

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion, then mark (1)
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark (2)
C. If assertion is true statement but Reason is false, then mark (3)
D. If both Assertion and Reason are false statements, then mark (4)

Answer

To solve the question, we need to analyze both the assertion (A) and the reason (R) provided.

### Step 1: Analyze the Assertion (A)
The assertion states that in an electromagnetic (EM) wave, the magnitude of the electric field vector (E) is more than the magnitude of the magnetic field vector (B).

From electromagnetic theory, we know that the relationship between the electric field (E) and the magnetic field (B) in an EM wave is given by the equation:
\[ E_0 = c \cdot B_0 \]
where \( c \) is the speed of light in a vacuum, approximately \( 3 \times 10^8 \, \text{m/s} \).

Since \( c \) is a very large number, it follows that:
\[ E_0 > B_0 \]
Thus, the assertion is correct.

### Step 2: Analyze the Reason (R)
The reason states that the energy of the EM wave is shared equally between the electric and magnetic fields.

To understand this, we can calculate the energy density associated with the electric and magnetic fields:
- The energy density due to the electric field is given by:
\[ u_E = \frac{1}{2} \epsilon_0 E^2 \]
- The energy density due to the magnetic field is given by:
\[ u_B = \frac{1}{2} \frac{B^2}{\mu_0} \]

Using the relationship \( E = cB \) and substituting \( c = \frac{1}{\sqrt{\mu_0 \epsilon_0}} \), we can show that:
\[ u_E = u_B \]
This means that the energy is indeed shared equally between the electric and magnetic fields in an EM wave. Therefore, the reason is also correct.

### Step 3: Conclusion
Both the assertion (A) and the reason (R) are correct. However, the reason does not correctly explain the assertion because the assertion is about the magnitudes of the fields, while the reason discusses energy density.

Thus, the final answer is:
- Assertion (A) is correct.
- Reason (R) is correct, but it is not the correct explanation for (A).

### Final Answer:
The answer is option B: Assertion is correct, Reason is also correct, but the Reason is not the correct explanation of the Assertion.

---