Question

A hair dryer draws 14.5 a when plugged into a 120-v line. assume direct current.

Answer 1

Missing part in the exercise. Complete text:
"A hair dryer draws 14.5 A when plugged into a 120-V line. Assume direct current.

(a) What is its resistance? Express your answer to two significant figures and include the appropriate units."

(b) How much charge passes through it in 11 min ? Express your answer to two significant figures and include the appropriate units.

Solution

(a) We can calculate the resistance by using Ohm's law:

`\Delta V= I R`

Since we know that
`\Delta V=120 V` and
`I=14.5 A`, we can find R:

`R= (\Delta V)/(I) = (120 V)/(14.5 A)=8.3 \Omega`

(b) The current is equal to the quantity of charge by unit of time:

`I= (Q)/(t)`

In our problem, t=11min=660 s, so we can calculate the charge passed through the hair dryer:

`Q=It=14.5 A \cdot 660 s = 9570 C`