Figure 14 shows an electrical circuit used to heat the windscreen of a car - AQA - GCSE Physics - Question 10 - 2023 - Paper 1

The equation that links charge flow (Q), energy (E), and potential difference (V) is given by:

$E = QV$

To find the charge flow (Q) through the battery, we can use the formula:

$E = QV$

Rearranging it gives:

$Q = \frac{E}{V}$

Substituting the values: $Q = \frac{5010 \text{ J}}{12 \text{ V}} = 417.5 \text{ C}$

The specific latent heat of fusion (L) can be calculated using the equation:

$L = \frac{E}{m}$

Where:

• E = 5010 J (energy transferred)
• m = 0.015 kg (mass of ice)

Substituting the values gives: $L = \frac{5010 \text{ J}}{0.015 \text{ kg}} = 334000 \text{ J/kg}$

As the ice melts, the particles undergo several changes:

1. Arrangement of Particles:

   • In the solid state (ice), particles are arranged in a regular and fixed pattern.
   • As the temperature rises, they begin to vibrate more vigorously.
   • Transitioning to the liquid state, particles become less ordered, adopting a random arrangement.

2. Movement of Particles:

   • The particles in ice are tightly packed and can only vibrate.
   • When energy is added through heating, the particles gain kinetic energy, increasing their movement.
   • As the ice melts, particles move freely, leading to a liquid state, allowing them to flow past one another.

3. Temperature Effects:

   • Throughout the melting process, the temperature remains constant until all the ice has melted.
   • Once melted, continued heating increases the particles' kinetic energy, raising the temperature to 5 °C.

4. Energy Transfer:

   • The electrical circuit provides energy, converting it into potential energy, contributing to the changes in the state of water as it melts.