1.

Design a voltage divider to supply a 22V, 10mA load and a 10V, 15mA from a 30V source. Assume the bleeder current is 10mA (ANS: R_S = 3380W @ 280mW, R₁ = 480W @ 300Mw, R_B = 1kW @ 100MW)

2.

Find the resistance of copper wire that is 200m long and 0.036mm in diameter. (ANS: R = 3380W)

3.

Determine the resistivity of manganin wire if the measured resistance is 1.7W when the diameter is 0.127cm and it is 5m long. (ANS: r = 43.1 x 10^-8 W ·m)

4.

Determine the resistance of #3 aluminum wire if it is 2 miles long. (ANS: R = 3.41W)

5.

Determine the wire size of an nickel wire if it has 6W/mile. (ANS: AWG #4 WIRE)

6.

At 0⁰C the resistance of a copper heater is 40W. How much current does it draw at 0⁰C and at 40⁰C, if it is connected to a 220V source. (ANS: I₀ = 5.5A, I₆₀ = 4.7A)

7.

What is the resistance of a tungsten stove element at 60⁰C if it draws 5A from a 120V source at 20⁰C. How much current does it draw at 60⁰C. (ANS: R = 28.3W, I = 4.24A)

8.

Determine the source voltage, and the correct wire size of a copper feeder to supply a 60hp, 200V motor that is located 300’ from a voltage source. The maximum voltage drop in the supply feeders is 4%. (ANS: V_T = 208.33V, AWG #000 WIRE)