Internal resistance and EMF

It is an energy supply by a battery/ electrical source to a coulumb unit of charge.

This refers to

• Potential difference

• Internal resistance

• Electromotive force

• Current

It is a work done or energy supply to move a unit of charge from 1 point to another point in a closed circuit

This refers to

• Internal resistance

• Potential difference

• Electromotive force

• Resistance

The cell has internal resistance, r, and electromotive force of 1.5 V.
What is the reading of voltmeter when the switch is closed?

• More than 3.0 V
• Less than 1.5 V
• More than 1.5 V
• 1.5 V

A battery has an e.m.f of 6.0 V. When it is connected to an external resistor, the potential different is 2.6 V and the current is 0.6 A. 
What is the value of the internal resistance?

• 3.4 Ω
• 4.3 Ω
• 4.4 Ω
• 5.7 Ω

What is the internal resistance of the battery in the circuit?

• 9.40 Ω
• 11.50 Ω
• 12.50 Ω
• 13.50 Ω

Which is a true statement?

• No sources of emf have internal resistance

• Some sources of emf have internal resistance

• Most sources of emf have internal resistance

• All sources of emf have internal resistance

What is emf?

• the electro motive "force" or the force on electrons

• the electromotive "force" or the Voltage of a cell measured when there is no current flowing

• the electromotive "field" or the Voltage of a cell measured when there is no current

• the electromotive "force" or Voltage of a cell measured when connected to a circuit

Correct

•  $\epsilon=V+Ir$  

•  $\epsilon=I\left(R+r\right)$  

•  $\epsilon=V$  

A battery of e.m.f. 12 V and internal resistance 1.5 Ω was connected to a 4.5 Ω resistor, what is the value for current?

• 4A

• 6A

• 2A

• 8A

A battery of e.m.f. 12.0 V, with an internal resistance of 3.0 Ω, is connected in series with a 15.0 Ω resistor and a battery of e.m.f. 9.0 V, which has an internal resistance of 2.0 Ω. Calculate the p.d. of the 15Ω resistor.

• 15.75V

• 5.25V

• 15.25V

• 15.50V