Home PYQs UPPSC UPPSC MCQs Prelims 2009 (GS Paper I)

Question

Of the two bulbs in a house, one glows brighter than the other. Which of the following statements is correct?

  1. The brightness does not depend on resistance
  2. Both the bulbs have the same resistance
  3. The brighter bulb has larger resistance
  4. The dimmer bulb has larger resistance.

Answer:

Option D: The dimmer bulb has larger resistance.

Detailed Solution:

The correct answer is “The dimmer bulb has larger resistance.”.

In a typical household circuit, bulbs are connected in parallel. The brightness of a bulb is determined by the power it dissipates, which can be calculated using the formula:

P = V^2 / R

​where P is the power (brightness), V is the voltage, and R is the resistance.

If the dimmer bulb has larger resistance: The power dissipated will be less for a given voltage, making it glow dimmer compared to the bulb with lower resistance.