Question

The current flowing through an inductor of self inductance ‘L’ is continuously increasing at constant rate. The variation of induced e.m.f. (e) versus `((dI)/(dt))`is shown graphically by:

1. 
   
2. 
   
3. 
   
4. 
   

Options

• A

• B

• C

• D

Answer 1

B

Explanation:

Given that, `((dI)/(dt))` = constant

∴ e = −L × constant

The negative sign indicates that the e.m.f. opposes the change.

Because the current is increasing (`((dI)/(dt))` is positive), the induced e.m.f. must be negative (plotted below the origin).

A direct proportionality with a negative constant results in a straight line passing through the origin in the fourth quadrant (downward).