Lesson test: Resistance and Ohm's law

1.[1p]
Ohm's law states that for an ohmic component

the current is directly proportional to the voltage across it

Correct

the current is inversely proportional to the voltage

The answer is: the current is directly proportional to the voltage across it

the voltage equals the resistance times the power

The answer is: the current is directly proportional to the voltage across it

the resistance changes with the current

The answer is: the current is directly proportional to the voltage across it

2.[2p]
A 220 ohm resistor has 5 V across it. What current flows, in milliamps? Give one decimal place.

CorrectNot quite: 22.7

4.[2p]
Resistance in a metal arises because

drifting electrons collide with the vibrating atoms of the lattice and lose energy

Correct

the metal has no free electrons

The answer is: drifting electrons collide with the vibrating atoms of the lattice and lose energy

the voltage is too low

The answer is: drifting electrons collide with the vibrating atoms of the lattice and lose energy

charge is destroyed in the wire

The answer is: drifting electrons collide with the vibrating atoms of the lattice and lose energy

5.[2p]
For a wire, $R = ρ L / A$ , so its resistance

rises with length and falls with cross-sectional area

Correct

falls with length and rises with area

The answer is: rises with length and falls with cross-sectional area

depends only on the material

The answer is: rises with length and falls with cross-sectional area

is independent of its shape

The answer is: rises with length and falls with cross-sectional area

6.[2p]
A 10 m copper wire has a resistance of 0.5 ohms. What is the resistance of a 30 m wire of the same material and thickness, in ohms?

CorrectNot quite: 1.5

7.[2p]
A filament lamp is ohmic, keeping a constant resistance as the voltage across it rises.

True

The answer is: False

False

Correct

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Resistance and Ohm's law

1.[1p]
Ohm's law states that for an ohmic component

2.[2p]
A 220 ohm resistor has 5 V across it. What current flows, in milliamps? Give one decimal place.

3.[2p]
What voltage, in volts, appears across a 1000 ohm resistor carrying 12 mA?

4.[2p]
Resistance in a metal arises because

5.[2p]
For a wire, $R = ρ L / A$ , so its resistance

6.[2p]
A 10 m copper wire has a resistance of 0.5 ohms. What is the resistance of a 30 m wire of the same material and thickness, in ohms?

7.[2p]
A filament lamp is ohmic, keeping a constant resistance as the voltage across it rises.

1.[1p] Ohm's law states that for an ohmic component

2.[2p] A 220 ohm resistor has 5 V across it. What current flows, in milliamps? Give one decimal place.

3.[2p] What voltage, in volts, appears across a 1000 ohm resistor carrying 12 mA?

4.[2p] Resistance in a metal arises because

5.[2p] For a wire, R=ρL/A, so its resistance

6.[2p] A 10 m copper wire has a resistance of 0.5 ohms. What is the resistance of a 30 m wire of the same material and thickness, in ohms?

7.[2p] A filament lamp is ohmic, keeping a constant resistance as the voltage across it rises.

1.[1p]
Ohm's law states that for an ohmic component

2.[2p]
A 220 ohm resistor has 5 V across it. What current flows, in milliamps? Give one decimal place.

3.[2p]
What voltage, in volts, appears across a 1000 ohm resistor carrying 12 mA?

4.[2p]
Resistance in a metal arises because

5.[2p]
For a wire, $R = ρ L / A$ , so its resistance

6.[2p]
A 10 m copper wire has a resistance of 0.5 ohms. What is the resistance of a 30 m wire of the same material and thickness, in ohms?

7.[2p]
A filament lamp is ohmic, keeping a constant resistance as the voltage across it rises.