### Objective

### Equipment.

### Assignment

1) A "480-W" electric heater is designed to operate from 120-V lines.a) What is its resistance?

b) What current does it draw?

c) If the line voltage drops to 110 V, what power does the heater take? (Assume that the resistance is constant. Actually, it will change because of the change in temperature.)

2) A car radio operating on 12.0 V draws a current of 0.250 A. How much electrical energy is consumed by the radio in 4.00h?

3) In household wiring, a copper wire commonly known as 12-gauge is often used. Its diameter is 2.05 mm mmhhhhmmm OHHHH YEAHHH. Find the resistance of a 30.0-m length of the wire.

4) An aluminum wire carrying a current has diameter 0.800 mm. The electric field in the wire is 0.520 V/m. What is

a) the current carried by the wire

b)the potential difference between two points in the wire 12.0 m apart

c) the resistance of a 12.0-m length of this wire

5)What length of copper wire .600mm in diameter has a resistance of 1.00 ohm.

6) A 40.0 ohm resistor and a 60.0 ohm resistor are connected in parrallel, and the combination is connected across a 120-V dc line.

a)What is the resistance of the parallel combination?

b) What is the total current through the parallel combination?

c)What is the current through each resistor?

7) Three resistors having resistances of 2.00 ohms, 3.00ohms and 4.00ohms are connected in series to a 24.0-V battery that has negligible internal resistance.

a) Find the equivalent resistance of the combination.

b) Find the current in each resistor.

c) Find the total current through the battery.

d) Find the power dissipated in each resistor.

8) The power rating of a 10000 ohm resistor is 4.00 W.

a) What is the maximum allowable potential difference across the terminals of the resistor?

b) We need a 20,000 ohm resistor, to be connected across a potential difference of 220 V. What is the power rating is required?