Energy, Power & Resistance

Question 1

Define Volt

Answer 1

1V is the p.d. across a component when 1J of energy is transferred per 1C passing through the component

Question 2

Define Electromotive Force (E.M.F.)

Answer 2

Energy transferred from chemical to electrical energy per unit charge

Question 3

Define Potential Difference

Answer 3

Energy transferred from electrical energy to thermal energy per unit charge.

Question 4

Resistance

Answer 4

V/I

Question 5

Ohm’s Law

Answer 5

P.d. across a conductor is directly proportional to the current in component so long as the temperature remains constant

Question 6

Kilo-Watt Hour

Answer 6

3.6MJ

Question 7

How can you determine the resistivity of a material in a lab? (5)

Answer 7

• Connect ends of ‘lead’ to a supply
• Ammeter = Series, Voltmeter = Across
• R = V/I
• Diameter = Micrometer, Length = Ruler
• Rho = (R X PiR^2)/L