The resistance of a coil is 5 ohm and a current of 0.2A is induced in it due to a varying magnetic field. The rate of change of magnetic flux in it will be-

Options

A. 0.5 W/b
B. 0.05 Wb/s
C. 1 W b/s
D. 20 Wb/s

Explanation

To solve the problem, we need to find the rate of change of magnetic flux (dΦ/dt) in the coil given its resistance (R) and the induced current (I).

### Step-by-Step Solution:

1. **Identify the given values:**
- Resistance of the coil, \( R = 5 \, \Omega \)
- Induced current, \( I = 0.2 \, A \)

2. **Use Ohm's Law to find the electromotive force (emf):**
The relationship between current, resistance, and emf is given by Ohm's Law:
\[ \text{emf} = I \times R \]
Substituting the known values:
\[ \text{emf} = 0.2 \, A \times 5 \, \Omega = 1 \, V \]

3. **Relate emf to the rate of change of magnetic flux:**
According to Faraday's law of electromagnetic induction, the emf (ε) induced in a coil is also equal to the rate of change of magnetic flux through the coil:
\[ \text{emf} = \frac{d\Phi}{dt} \]
Therefore, we can write:
\[ \frac{d\Phi}{dt} = 1 \, Wb/s \]

4. **Conclusion:**
The rate of change of magnetic flux in the coil is:
\[ \frac{d\Phi}{dt} = 1 \, Wb/s \]

### Final Answer:
The rate of change of magnetic flux in the coil is \( 1 \, Wb/s \).

---