Given:
The current drawn by the hair dryer is: I = 9 A
The voltage applied to the hair dryer is: V = 120 v
The time for which the charge passes is: t = 15 min = 15 × 60 s = 900 s
To find:
a) The resistance
b) Charge passing through the resistor in 15 mins
Step-by-step explanation:
a)
The expression for potential difference (V) in terms of current (I) and resistance (R) is given as:

Rearranging the above equation, we get:

Substituting the values in the above equation, we get:

b)
The electric current (I) through the conductor is defined as the amount of charge (Q) passing through the conductor per unit time (t). It is given as:

Rearranging the above equation and substituting the values in it, we get:

Final answer:
a) The resistance is 13.33 Ω
b) The charge passing for 15 mins is 8100 C.