Unit 2- Electricity

Question 1

Coulomb

Answer 1

1 coulomb = 1 ampere second

Question 2

Volt

Answer 2

1 volt =

1 joule per coulomb

Question 3

Ohm

Answer 3

1 ohm = 1 volt per amp

Question 4

Kilowatt-hour

Answer 4

Energy equal to 1kW for 1 hour

Question 5

Electric Current

Answer 5

A net flow of charged particles

Question 6

Conventional Current

Answer 6

Current moves from positive to negative (of battery in circuit) and electrons move from negative to positive

Question 7

Drift velocity

Answer 7

The mean displacement of electrons along the wire per second

Question 8

Resistance

Answer 8

Resistance = potential difference / current

Question 9

Ohm’s Law

Answer 9

Potential difference is proportional to current, provided that the temperature and other physical conditions remain constant

Question 10

Resistivity

Answer 10

Resistivity = resistance X cross-sectional area / length

Question 11

Potential difference

Answer 11

Energy transferred per unit charge from electrical energy to other forms of energy

Question 12

Electromotive Force

Answer 12

Energy transferred per unit charge from some other form to electrical energy

Question 13

Kirchhoff’s First Law

Answer 13

Sum of currents entering a junction equals the sum of currents leaving a junction; true because charge is conserved

Question 14

Kirchhoff’s Second Law

Answer 14

Around a closed loop in a circuit, the sum of the e.m.f.s equals the sum of the p.d.s; true because energy is conserved

Question 15

Internal Resistance

Answer 15

Energy is transferred to thermal energy in the battery, so it behaves as if it had a resistance

Question 16

Terminal p.d.

Answer 16

Terminal p.d. is less than e.m.f because internal resistance causes some energy to be transferred to thermal energy in the battery