Question

A heater joined in series with a $3W$ bulb is connected to the mains. If the $3W$ bulb is replaced by a $11W$ bulb, the heat produced by the heater is

• A. Increases
• B. Decreases
• C. Remains same
• D. None of these

Answer 1

Answer: (B)

Decreases

Resistance of $11W$ bulb is greater than that of $3W$ bulb.
So, resistance is increases in series and the current through the circuit decreases.
Hence, the heat produced by the heater $(H=I^{2}RT)$ decreases.