Electromotive Force and Internal Resistance

The electromotive force, E (e.m.f.) is defined as the work done by a source in driving __________________ around a complete circuit.

• 1 A of electric current

• 1 coulomb of charge

The voltage label on a battery or cell indicates its _________.

• e.m.f

• current

A cell has an e.m.f. of 1.5 V if a flow of

1 C of charge produces ______ of electrical energy to the whole circuit.

• 1.5 J

• 1.0 J

When circuit is opened, _____________ flows through the circuit.

• there are current

• no current

A cell with e.m.f. 2 V and internal resistance 1 Ω is connected to a resistor of 4 Ω. What is the reading on the voltmeter when it is connected across the 4 Ω resistor?

• 1.6 V

• 8 V

A bulb M is connected to a battery by means of a switch. A voltmeter is also connected across the battery. When the switch is open, the voltmeter reads 6.0 V. When the switch is closed, the voltmeter reads 4.8 V.

6(a) What is the e.m.f. of the battery?

• 6.0 V

• 4.8 V

A bulb M is connected to a battery by means of a switch. A voltmeter is also connected across the battery. When the switch is open, the voltmeter reads 6.0 V. When the switch is closed, the voltmeter reads 4.8 V.

6(b) If the resistance of the bulb M is 8 Ω, what is the current passing through M when the switch is closed?

• 38.4 A

• 0.6 A

A bulb M is connected to a battery by means of a switch. A voltmeter is also connected across the battery. When the switch is open, the voltmeter reads 6.0 V. When the switch is closed, the voltmeter reads 4.8 V. 
6(c) Find the value of the internal resistance, r, of the battery.

• 2 ohm

• 4 ohm

Electrical energy is defined as the ability of ____________________.

• the electric current to do work

• the fuses to stop electric current

Electrical energy can be converted by an electrical appliance into ______________ such as heat, light, mechanical when current flows in it.

• in the form of force

• other forms of energy