Vani’s hair dryer has a resistance of 50 Ω when it is first turned on.

i) How much current does the hair dryer draw from the 230 V – line in Vani’s house?

ii) What happens to the resistance of the hair dryer when it runs for a long time?

(Hint: As the temperature increases the resistance of the metallic conductor increases.)

At time t = 0, the given initial resistance(R) of the hair dryer is 50 ohm

i). We are given with the input voltage(V) = 230 V and we have to find the amount of current withdrawn by the dryer which is actually the initial current drawn by the dryer, so,

By using ohm’s law, we will calculate the current,

V = I× R,

ii). As we know that the dryer is used to dry our hair and it does by throwing hot air on us and as time passes when we are using it, it becomes hot and when it’s temperature is increased by becoming hot, the resistance of the metallic parts increases , the resistance of the metals increases with the increase in temperature till a certain temperature or within a specific range. The longer we use the hair dryer the more hot it becomes and the more resistance is offered by it.