Home Chapter 18 Practice Questions

# Practice Questions

This activity contains 25 questions.

## The unit for measuring current is the

 volt. ohm. ampere. ohm-m.

## The unit for measuring resistance is the

 ampere. volt. ohm. ohm-m.

## In a simple circuit a voltage of 5 volts is applied across a resistance of 10 ohms. The current in the circuit is

 50 A 5 A .5 A .1 A

## The power dissipated in the resistor in the previous question is

 .5 watts. 2.5 watts. 5 watts. 50 watts.

## What is the power drawn from the battery in question 3?

 .5 watt 2.5 watt 5 watt 50 watt

## A flashlight bulb draws 2.5 amps when connected to two C cells (3 volts). What is its resistance?

 .83 ohm 1 ohm 1.2 ohm 2.4 ohm

## What is the power disipated in the bulb in Question 6?

 3 W 3.6 W 7.5 W None of the above.

## A lantern bulb with a resistance of 4 ohms draws 1.5 A when connected to a certain battery. The battery voltage is

 1.5 V. 2.7 V. 4 V. None of the above.

## A 1000 watt appliance is used 10 hours a day for 28 days per month. If the cost of electricity is \$.10 a kwh (kilowatt-hour), how much does it cost to operate the appliance for a month?

 \$10 \$28 \$67 \$200

## What is the cost of electricity in mils/J if it costs \$.10 per kwh? (A mil is 1/1000 cent).

 zero .00005 .0028 .17

## One billion electrons pass a certain point in a micro second. This corresponds to a current of

 .00000016 A .00016 A 1 x 1015 None of the above.

## Three amps corresponds to how many electrons per seconds?

 1 x 1019 1.5 x 1019 1.9 x 1019 3 x 1019

## What is the 'average' (rms) speed of the electrons in a wire at 30oC?

 3.7 x 104 m/s 1.17 x 105 m/s 3 x 108 m/s 4.5 x 108 m/s

## A 2 amp current flows in a conductor which has 1 x 1024 free electrons per meter. What is their average drift velocity in the direction of the current?

 1.25 m/s 125000 m/s 3 x 108 m/s 1.25 x 10-5 m/s

## If the circuit in the above question is a 20 foot long wire in your automobile, how long would it take an electron to travel from the negative terminal to the positive terminal of the battery?

 1 second 2 hours 1 week 6 days

## Two otherwise identical wires are made of different materials, the second having twice the resistivity of the first. The first has a resistance of 2 ohms, the second has a resistance of

 1 ohm 3 ohms 4 ohms Not enough information is given.

## Two aluminum wires have the same diameter but the second is twice as long as the first. If the first has a resistance of 2 ohms, the resistance of the second is

 1 ohm. 3 ohms. 4 ohms. 8 ohms.

## Two copper wires have the same length but the second has twice the diameter of the first. If the resistance of the first is 2 ohms, the resistance of the second is

 1/2 ohm. 1 ohm. 4 ohms. 8 ohms.

## What is the resistance of a 10 km long copper wire with a diameter of 4mm?

 3.3 ohms 13.4 ohms .013 ohms .003 ohms

## If the wire in the above question has a resistance of 10 ohms and is transmitting 10 kW at 1000 volts, how much power is lost in the wire?

 10 W 100 W 1 kW 10 kW

## If the power in the above question is being transmitted at 10000 volts, what is the power loss in the wire?

 1 W 10 W 1 kW 10 kW

## If the peak AC voltage is 150 volts, what is the rms voltage?

 75 volts 106 volts 120 volts 212 volts

## If the rms current is 30 amps, what is the peak current?

 21 A 30 A 35 A 42.5 A

## One thousand peak AC watts is how many rms watts?

 500 W 707 W 1414 W 2000 W

## What is the internal resistance of a 1500 watt electric space heater operating at a standard house voltage of 120 V?

 19.2 ohms 13.6 ohms 9.6 ohms 6.8 ohms