iGCSE Physics Electrical resistance

Which of the following links voltage, current and resistance?

• V = I × A

• R = V × A

• V = I × R

• R = I/V

Which is the unit of resistance?

• amps

• coulombs

• volts

• ohms

A radio is supplied with 36 V. The current through the radio is 0.2 A. What is the resistance of the radio?

• 180 Ω

• 76 Ω

• 0.06 Ω

• 76 C

An electric shower is connected to the 230 V mains. The resistance of the shower is 120 Ω. What is the current through the wire for the shower?

• 0.2 A

• 2.0 A

• 0.5 A

• 5.0 A

Two resistors of resistance 7 Ω and 8 Ω respectively are placed in a series circuit. What is their total resistance?

• 8 Ω

• 15 Ω

• 56 Ω

• 0.9 Ω

A 12 V supply is connected to a series circuit containing two resistors which each have a resistance of 3 Ω. What is the current flowing through the circuit?

• 4 A

• 0.25 A

• 2 A

• 0.5 A

Which of the following components follows Ohm’s law when at a constant temperature?

• diode

• LDR

• resistor

• thermistor

Which component does this I–V graph represent?

• diode

• filament bulb

• wire

• resistor

Which component does this I–V graph represent?

• diode

• wire

• filament bulb

• resistor

Which of the following represents the gradient of an I–V graph?

• 1/resistance

• resistance

• total charge

• none of the above