Circuit Activity

When lighted, a 100-watt light bulb operating on a 110-volt household circuit has a resistance closest to

• 10^-2 Ω

• 10^-1 Ω

• 1 Ω

• 10 Ω

• 100 Ω

The five resistors shown below have the lengths and cross-sectional areas indicated and are made of material with the same resistivity. Which has the greatest resistance?

• A

• B

• C

• D

• E

A 30-ohm resistor and a 60-ohm resistor are connected as shown above to a battery of emf 20 volts and internal resistance r. The current in the circuit is 0.8 ampere. What is the value of r?

• 0.22 Ω

• 4.5 Ω

• 5 Ω

• 16 Ω

• 70 Ω

Which of the following combinations of 4Ω resistors would dissipate 24 W when connected to a 12 Volt battery?

• A

• B

• C

• D

• E

The circuit in the figure above contains two identical lightbulbs in series with a battery. At first both bulbs glow with equal brightness. When switch S is closed, which of the following occurs to the bulbs?

• 1 Goes out, 2 Gets brighter

• 1 Gets brighter, 2 Goes out

• 1 Gets brighter, 2 Gets slightly dimmer

• 1 Gets slightly dimmer, 2 Gets brighter

• 1 Nothing, 2 Goes out

When the switch S is open in the circuit shown above, the reading on the ammeter A is 2.0 A. When the switch is closed, the reading on the ammeter is

• doubled

• increased slightly but not doubled

• the same

• decreased slightly but not halved

• halved

In the circuit shown above, the equivalent resistance of the three resistors is

• 10.5 Ω

• 15 Ω

• 20 Ω

• 50 Ω

• 115 Ω

A galvanometer(a device to measure very weak current) has a resistance of 99 ohms and deflects full scale when a current of 10^-3 ampere passes through it. In order to convert this galvanometer into an ammeter with a full-scale deflection of 0.1 ampere, one should connect a resistance of

• 1 Ω in series with it

• 901 Ω in series with it

• 9,900 Ω in series with it

• 1 Ω in parallel with it

• 9,900 Ω in parallel with it