Question

Air cored choke coil and delectric bulb are connected in series with $A.C$. mains. A soft iron rod is inserted in coil then the intensity of electric bulb will be :

• A. decrease
• B. increase
• C. fluctuate
• D. unchanged

Answer 1

Answer: (B)

increase

Answer 2

When a soft iron rod is inserted into the coil then its magnetism increases, due to which induced e.m.f. increase and it will oppose the external c.m.f. so e.m.f. across bulb increases, so the intensity of bulb increases.