The current flowing in two coaxial coils in the same direction. On increasing the distance the two, the electric current will

Options

A. remain unaltered
B. increase in one and decrease in the second
C. increase in both
D. decrease in both

Explanation

To solve the question regarding the behavior of electric current in two coaxial coils when the distance between them is increased, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Configuration**: We have two coaxial coils carrying current in the same direction. Let's denote the current in both coils as \( I \).

2. **Identify the Effect of Distance**: When the distance between the two coils is increased, the magnetic flux linkage between the coils will change. The magnetic field produced by one coil will be weaker at the location of the other coil as the distance increases.

3. **Apply Lenz's Law**: According to Lenz's Law, if there is a change in magnetic flux through a coil, an induced current will flow in a direction that opposes the change in flux. In this case, as the distance increases, the magnetic flux linkage decreases.

4. **Determine the Induced Current**: To counteract the decrease in magnetic flux linkage due to the increased distance, the coils will induce a current in such a way that it tries to maintain the original flux linkage. Therefore, the current in both coils must increase to compensate for the reduction in magnetic flux.

5. **Conclusion**: Since both coils are in the same direction and the induced current will increase in both coils, we conclude that the current in both coils will increase.

### Final Answer:
The current flowing in both coils will **increase** when the distance between them is increased.