Prove Ur Current Right!

In the circuit shown, 2.0 C of charge move through the lamp in a time of 6.0 s.

What is the current in the circuit?

• 0.33 A

• 3.0 A

• 4.0 A

• 12 A

A 6.0 V electrical heater is switched on and transfers 360 J of electrical energy to thermal energy in a time of 2.0 minutes.

What was the current in the heater?

• 0.033 A

• 0.5 A

• 2.0 A

• 30 A

The diagram shows a circuit containing a variable resistor R.

The resistance of R is increased.

Which row correctly describes the changes to the ammeter and voltmeter readings?

• Ammeter reading - decrease

  Voltmeter reading - decrease

• Ammeter reading - decrease

  Voltmeter reading - increase

• Ammeter reading - increase

  Voltmeter reading - decrease

• Ammeter reading - increase

  Voltmeter reading - increase

The circuit shown is used to determine the resistance of a lamp for two different brightness settings.

When the brightness of the lamp is low, the voltmeter reading is 2V and the ammeter reading is 2 A.

When the brightness of the lamp is normal, the readings are 12 V and 4 A.

What is the increase in filament resistance?

• 1 Ω

• 2 Ω

• 3 Ω

• 4 Ω

The diagram shows a 16 V battery connected to three resistors in series.

What is the value of resistor R?

• 1.0 Ω

• 3.0 Ω

• 4.0 Ω

• 7.0 Ω

A mobile phone (cell phone) takes 4.0 hours to fully recharge from a 5.0 V power supply. The charging current is 0.25 A.

How much electrical energy is transferred from the power supply?

• 3.0 J

• 300 J

• 700 J

• 18000 J

The diagram shows a lamp connected in series with a resistor.

The current in the lamp is 0.5 A.

Which row gives the correct voltmeter and ammeter readings?

• Voltmeter = 0.5 V

  Ammeter = 1.0 A

• Voltmeter = 1.0 V

  Ammeter = 0.5 A

• Voltmeter = 3.0 V

  Ammeter = 0.5 A

• Voltmeter = 3.0 V

  Ammeter = 1.5 A

A 12V lamp uses a current of 2A.

What is the resistance when the lamp is working correctly?

• 6 Ω

• 10 Ω

• 14 Ω

• 24 Ω

Two resistors are connected in a circuit as shown.

The reading on the voltmeter V1 is 2 V.

Which statement is correct?

• The current in the 5 Ω resistor is greater than the current in the 10 Ω resistor.

• The current in the 10 Ω resistor is 20 A.

• The electromotive force of the cell is 3 V.

• The reading of the voltmeter V2 is 4 V.

A 2 kW electric heater is connected to a 240 V supply.

What is the current in the heater?

• 0.12 A

• 8.3 A

• 120 A

• 480 A