Electricity

Question 1

Current

Answer 1

Rate of flow of charge in a circuit

Question 2

Emf (Electromotive force)

Answer 2

The amount of electrical energy transferred by a source, to each unit of charge that passes through it

Question 3

Internal resistance

Answer 3

The resistance to the flow of charge within a source, results in energy being dissipated within the source

Question 4

Ohmic conductor

Answer 4

A conductor which the current flow is directly proportional to the potential difference across it, given that the physical conditions remain constant

Question 5

Ohm’s law

Answer 5

Current and potential difference across an ohmic conductor held under constant physical conditions are directly proportional, with constant the constant of proportionality being resistance

Question 6

Potential divider

Answer 6

A method of splitting potential difference by connecting two or more resistors in series with a fixed power source, total p.d. is split in the ratio of their resistance

Question 7

Resistance

Answer 7

A material’s opposition to the flow of charge

Question 8

Resistivity

Answer 8

A quantity that’s proportional to an object’s resistance and cross-sectional area, and inversely proportional to the object’s length

Question 9

Superconductor

Answer 9

A material that has zero resistivity when the temperature is decreased to or below its critical temperature. They are used to produce strong magnetic fields and reduce energy loss when transmitting electric power

Question 10

Terminal potential difference

Answer 10

Potential difference across the terminals of a power source
= source’s emf - voltage lost from source’s internal resistance