An em wave is propagating in a medium whith a velocity `vecv=vhati`. The instantaneous oscillating electric field of this of em wave is along `+y` axis. Then the direction of oscillating magnetic field of the em wave will be along

Options

A. `-x` direction
B. `-z` direction
C. `-y` direction
D. `+z` direction

Explanation

To determine the direction of the oscillating magnetic field of an electromagnetic (EM) wave given that the electric field is oscillating along the +y axis and the wave is propagating in the +x direction, we can use the right-hand rule. Here’s a step-by-step solution:

### Step 1: Identify the directions of the electric field and wave propagation
- The electric field (E) is given to be oscillating along the +y axis. This can be represented as:
\[ \vec{E} = E \hat{j} \]
- The wave is propagating in the +x direction, which can be represented as:
\[ \vec{v} = v \hat{i} \]

### Step 2: Use the right-hand rule to find the direction of the magnetic field
- According to the right-hand rule for electromagnetic waves, if you point your thumb in the direction of wave propagation (which is +x or \(\hat{i}\)), and your fingers in the direction of the electric field (which is +y or \(\hat{j}\)), your palm will face in the direction of the magnetic field (B).

### Step 3: Apply the right-hand rule
- Point your thumb in the direction of \(\hat{i}\) (the +x direction).
- Curl your fingers in the direction of \(\hat{j}\) (the +y direction).
- Your palm will then point in the direction of the magnetic field, which will be along the +z axis.

### Step 4: Conclusion
- Therefore, the direction of the oscillating magnetic field (B) of the EM wave will be along the +z axis:
\[ \vec{B} = B \hat{k} \]

### Final Answer
The direction of the oscillating magnetic field of the EM wave will be along the +z axis.

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