Question

1. When S₁ close bulb glows instantaneously when S₂ closes there is a delay in glowing the bulb.

This is due to……… 

• resistance of the coil 
• back emf in the coil 
• mutual induction
• none

2. Explain the phenomenon self-induction regarding above experiment 

3. Draw the graph with energy and current for a inductor. 

Answer 1

1. Back emf in the coil. 

2. When a.c. current is passed through the coil, a change in flux is produced. This change in flux produces a back e.m.f. in the coil. The phenomena of production of back emf is called self induction.

3. The graph with energy and current for a inductor: