Potential difference and electromotive force

The volt
1. 1V = 1JC^-1
2. One volt is the p.d. across a component when 1J of energy is transferred per unit charge passing through the component
3. Potential difference is measured in volts
4. Potential difference is the energy transferred from electrical energy to other forms (heat,light, etc.) per unit charge
  1. P.d. is used when charged particles lose energy in a component
  2. V = W / Q
    1. V is p.d. measured in volts
    2. W is the energy transferred by charge
    3. Q is charge in couloumbs
  3. When work id done by the charge carriers
The voltmeter
1. A voltmeter is used to measure p.d.
2. It is connected in parallel across a particular component
3. An ideal voltmeter has an infinite resistance
  1. When connected, no current passes through the voltmeter itself
Electromotive force
1. When work is done on the charge carrier
2. Charges are gaining energy as they pass through a component
3. The greater the e.m.f. the more energy per coulomb has been transferred into electrical energy
  1. Sources of e.m.f. include solar cells, dynamos, and thermocouples
4. ε = W/Q
  1. Q is charge in coulombs
  2. W is the energy transferred
  3. ε is e.m.f. measured in volts
5. E.m.f. is used when charged particles gain energy from a source
6. The energy transferred from chemical energy to electrical energy per unit charge
Calculating energy transfer
1. W = VQ
2. W = εQ
3. The energy transferred from or to the charges can be calculated from the defining equations

Resource summary

	Created by Rebecca Shoesmith over 8 years ago