Electricity

Question 1

What’s an ampere?

Answer 1

The unit of measure for the rate of flow

Question 2

State Ohms Law

Answer 2

The value of a current passing through a conductor is directly proportional to the potential difference between the ends of the conductor and inversely proportional to the resistance of the conductor

Question 3

What factors effect the resistance of a circuit?

Answer 3

• The length of a conductor
• The cross-sectional area of the conductor
• The conductivity of the material used
• Temperature

Question 4

Which 2 currents supply electricity?
Explain each one

Answer 4

Alternating current - current constantly changes direction.
Direct current - electrons flow through the conducting material in 1 direction

Question 5

Name 2 protective devices fitted in electric circuits?

Answer 5

Fuses
Circuit breakers

Question 6

How do you calculate the power output of a DC appliance?

Answer 6

Power (Watts) = R (Ohmms) x I (Amps) squared

Where R = resistance
I = Current

Question 7

How do the majority of fires with electrical origin start?

Answer 7

Poor insulation
Poor/lack of maintenance of electrical systems
Mis-use of electrical systems/appartus

Question 8

What is the formula used to workout resistance?

Answer 8

Resistance (Ohms)= Voltage (Volts) ÷ Current (Amperes)

Question 9

What is the relationship between voltage, current and resistance?

Answer 9

Ohms law

Question 10

How does current differ to voltage?
What is the relationship between them?

Answer 10

Current - measure of the number of electrons passing a particular point in a conductor.

Voltage - the pressure applied that causes electrons to flow

The greater the applied voltage, the greater the current flowing