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• What is meant by direct potential difference?

  Potential difference where the direction doesn’t change.
• Which equation links charge flow (Q), energy (E) and potential difference (V)?

  E = QV
• Calculate the charge flow through a 12V battery when the battery transfers 5010J of energy.

  5010 = Q × 12

  Q = 5010 / 12

  Q = 417.5C
• Ice forms on a windscreen at a temperature of 0°C. The electrical circuit transfers 5010J of energy to the ice. A mass of 0.015kg melts. Calculate the specific later heat of fusion in water.

  5010 = 0.015 × L

  L = 5010 / 0.015

  L = 334,000J/kg
• Explain the changes in the arrangement and movement of the particles as ice melts.

  As the ice changes to water, the temperature remains constant because the potential energy of the particles increases. Kinetic energy also increases as the particles move faster when heated. The particles change from a regular pattern to a random arrangement and move freely compared to their previous stationary vibrations.