A student investigated how much energy from the Sun was incident on the Earth's surface at her location - AQA - GCSE Physics - Question 12 - 2018 - Paper 1

The equation that links energy transferred, power, and time is:

$E = P imes t$

where $E$ is the energy transferred, $P$ is the power, and $t$ is the time.

To calculate the mean power supplied, we can use the formula:

P = rac{E}{t}

Substituting the known values:

P = rac{1050 ext{ J}}{5 ext{ minutes} imes 60 ext{ seconds/minute}} = rac{1050}{300} = 3.5 ext{ W}

We can use the specific heat capacity equation:

$E = m imes c imes heta$

Rearranging for mass $m$ gives:

m = rac{E}{c imes heta}

Substituting the known values:

m = rac{1050 ext{ J}}{4200 ext{ J/kg °C} imes 0.6 °C} = rac{1050}{2520} = 0.417 ext{ kg}

One reason is that the intensity of solar radiation may have varied during the investigation, affecting the total energy received by the water.