A 100W bulb is connected in series with a room heater. If now 100W bu...
Hence, the correct option is (A)
A 100W bulb is connected in series with a room heater. If now 100W bu...
Question Analysis:
We are given that a 100W bulb is connected in series with a room heater. Our task is to determine what happens to the heater output when the 100W bulb is replaced by a 40W bulb.
Answer Explanation:
To understand the effect of replacing the bulb on the heater output, we need to consider the concept of series circuits and power.
Series Circuits:
In a series circuit, the current flowing through each component is the same. This means that the current passing through the bulb is equal to the current passing through the heater.
Power:
The power consumed by a device can be calculated using the formula:
Power = Voltage x Current
Effect of Replacing the Bulb:
1. When the 100W bulb is connected in series with the heater, the total power consumed by the circuit is the sum of the power consumed by the bulb and the power consumed by the heater. Let's denote the power consumed by the heater as P1.
Total Power = Power consumed by bulb (100W) + Power consumed by heater (P1)
2. Now, when the 100W bulb is replaced by a 40W bulb, the total power consumed by the circuit changes. Let's denote the power consumed by the heater with the 40W bulb as P2.
Total Power = Power consumed by 40W bulb + Power consumed by heater (P2)
3. Since the current passing through the circuit remains the same in a series circuit, the power consumed by the heater must be the same in both cases. This means that P1 = P2.
Conclusion:
When the 100W bulb is replaced by a 40W bulb, the power consumed by the heater remains the same. Therefore, the heater output will decrease because the total power consumed by the circuit decreases. This decrease in power consumption is due to the lower power rating of the 40W bulb.
Key Points:
- In a series circuit, the current passing through each component is the same.
- Power consumed by a device can be calculated using the formula: Power = Voltage x Current.
- When the 100W bulb is replaced by a 40W bulb, the power consumed by the heater remains the same.
- The heater output will decrease when the 100W bulb is replaced by a 40W bulb.