Current electricity

The SI unit of electric current is the:

• 1 Volt
• 2 Watt
• 3 Ohm
• 4 Ampere

Ohm's law states that V is equal to:

• 1 I + R
• 2 I x R
• 3 R / I
• 4 I / R

A 12 V battery drives a current of 3 A through a resistor. What is its resistance?

• 1 4 ohm
• 2 36 ohm
• 3 0.25 ohm
• 4 9 ohm

Two 6 ohm resistors are connected in parallel. Their combined resistance is:

• 1 36 ohm
• 2 3 ohm
• 3 6 ohm
• 4 12 ohm

A 100 W bulb runs for 10 hours. How many kilowatt hours of energy does it use?

• 1 100 kWh
• 2 0.1 kWh
• 3 1 kWh
• 4 10 kWh

Which device is connected in series in a circuit to measure current?

• 1 Voltmeter
• 2 Galvanometer in parallel
• 3 Rheostat
• 4 Ammeter

The resistance of a wire increases when its length:

• 1 Stays the same
• 2 Decreases
• 3 Becomes zero
• 4 Increases

A fuse in a circuit is used to:

• 1 Store charge
• 2 Increase current
• 3 Protect against too much current
• 4 Measure voltage

In a series circuit the current is:

• 1 Zero
• 2 Different in each part
• 3 The same everywhere
• 4 Infinite

The potential difference across 2 ohm carrying 3 A is:

• 1 1.5 V
• 2 5 V
• 3 6 V
• 4 0.67 V