The resistance of a torch bulb is 1 ohm. When it is connected to a source of 3 V, it draws a current of 0.3 A. Calculate the resistance of the bulb when glowing.

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Solution

When not connected to the source the resistance of the bulb is 1 Î©. So, the current is, I = V/R
= > I = 3/1 = 3 A
Now, when the bulb is glowing the temperature of its filament increases and hence its resistance also increases. So, the new resistance is, R = V/I = 3/0.3 = 10 Î©

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The resistance of a torch bulb is 1 ohm. When it is connected to a source of 3 V, it draws a current of 0.3 A. Calculate the resistance of the bulb when glowing.

When not connected to the source the resistance of the bulb is 1 Î©. So, the current is, I = V/R= > I = 3/1 = 3 ANow, when the bulb is glowing the temperature of its filament increases and hence its resistance also increases. So, the new resistance is, R = V/I = 3/0.3 = 10 Î©

When not connected to the source the resistance of the bulb is 1 Î©. So, the current is, I = V/R
= > I = 3/1 = 3 A
Now, when the bulb is glowing the temperature of its filament increases and hence its resistance also increases. So, the new resistance is, R = V/I = 3/0.3 = 10 Î©