Question

When a light bulb is connected to a 4.5 V battery, a current of 0.12 A passes through the bulb filament. What is the resistance of the filament? A) 440 Ω B) 28 Ω C) 9.3 Ω D) 1.4 Ω E) 38 Ω

Answer 1

Answer:

Option (E) 38 ohm

Explanation:

Voltage, V = 4.5 V

Current, i = 0.12 A

Let r be the resistance of the filament of the bulb.

By use of Ohm's law

V = i x R

4.5 = 0.12 x R

R = 4.5 /  0.12 = 37.5 Ohm

By rounding off

R = 38 ohm