Question

Of the two bulbs in a house, one glows brighter than the other. Which of the two has a large resistance?
A. The bright bulb
B. The dim bulb
C. Both have the same resistance
D. The brightness does not depend on the resistance.

Answer 1

Hint:There are two given bulbs of which one bulb glows brighter than another. This can be directed related to the power of the bulb. Brighter the bulb is, more is the power. Less bright the bulb is, the power is lowered. Power inversely depends on resistance. Therefore higher the resistance, less power is delivered to the bulb.

Formula Used:
The electric power \[P\] is given by: \[P = \dfrac{{{V^2}}}{R}\]
where, \[V\] is the potential difference and \[R\] is the resistance.

Complete step by step answer:
The rate of dissipation of electric energy is called electric power. The electric power \[P\] is given by
\[P = \dfrac{{{V^2}}}{R}\]
where, \[V\]is the potential difference and \[R\] is the resistance.
Therefore, the power is inversely proportional to the resistance. If the bulb is brighter, then it has more power and therefore has less resistance. On the other hand, if the bulb is dim, then it has less power. And, its value of resistance is large. Therefore, the dim bulb has a large resistance.

Hence, option B is the correct answer.

Note:If one bulb glows brighter than the other, it can be thought that the bulb has a low voltage. But in household circuits all electrical appliances are connected in parallel. Due to this equal voltage is supplied to all the appliances. Also if any of the electrical devices turns defective, other devices will continue to work in a parallel connection.