SCEN103 Spring 2000 Individual Quiz

Name: ______________________

Group: ______________________

1. Consider the following circuit that represents a small penlight, one alkaline AAA cell connected to a lamp. The AAA cell provides 1.5 V and has an internal resistance r of 0.6 ohms. The lamp resistance R may be assumed to be 7.0 ohms.

a. What is the current through the lamp?

b. What is the voltage across the lamp?

c. How much of the AAA cell’s power is wasted by its internal resistance?

2. During the Play-Doh lab exercise a cylinder was rolled out to have a circumference of 6 cm. It was observed to have a resistance of 60 ohm along a 10 cm length. Next the cylinder was rolled down to a circumference of 3 cm – what should its new resistance be along 10 cm?