1) A hair dryer draws a current of 11.5 A.
(a) How much charge passes through the hair dryer in 3.5 min?
(b) How many electrons does this represent?
2) The operating potential difference of a light bulb is 120 V. The power rating of the bulb is 45 W. Find the:
(a) current in the bulb
(b) the bulb's resistance.
3) A steam iron draws 8.0 A when connected to a potential difference of 120 V.
(a) What is the power rating of this iron?
(b) How many joules of energy are produced in 20.0 min?
(c) How much does it cost to run the iron for 20.0 min at $0.010/kW·h?
4) An 18.0 W energy-efficient fluorescent lamp is designed to produce the same illumination as a conventional 50.0 W lamp.
(a) How much energy does this lamp save during 100.0 h of use?
(b) If electrical energy costs $0.080/kW·h, how much money is saved in 100.0 h?
5) A 6.0 resistor, an 12.0 resistor, and a 18.0 resistor are connected in series with a 24 V battery.
(a) Determine the equivalent resistance for the circuit.
(b) Determine the current in the circuit.
6) An 24.0, 9.0, and 3.0 resistor are connected in series with an emf source. The current in the 9.0 resistor is measured to be 4.00 A.
(a) Calculate the equivalent resistance of the three resistors in the circuit.
7) An 21.0, 9.0, and 6.0 resistor are connected in parallel across a 12 V battery.
(a) Determine the equivalent resistance for the circuit.
(b) Determine the current in the circuit.