# Homework Help: Solar energy calculation - help needed

1. Nov 5, 2007

### marclee85

Hi, I am new to this forum and wondering if anybody would be kind enough to help me.

A solar panel of area 2 m2 absorbs solar energy at the rate of
950 W/m2. Assuming that all the energy is used to heat water
in a 110 litre tank how long would it take for the water
temperature to increase from 15C to 65C?

This is the only question I am really stuck on in my Revision Paper as I havent covered this area before.

2. Nov 5, 2007

### Kurdt

Staff Emeritus
Welcome to PF! The forum rules require you to show what you've tried so far before anyone can help you.

Have you come across the heat energy equation before?

3. Nov 5, 2007

### marclee85

The difficulty I am encountering is that nothing of this sort is in the text books recommended to me and I cant seem to find anything on the internet either.

I really do not know where to start with this, can you shed some light or give me a relevant link that will assist me?

Thankyou very much for your help.

4. Nov 5, 2007

### Kurdt

Staff Emeritus
Well I gave you a small hint above mentioning the heat energy equation. If you searched for it you would probably come across it. Here it is anyway in case you get confused with other heat equations.

$$Q = mc_p \Delta T$$

where Q is the heat energy, m is the mass of the substance, cp is the specific heat capacity of the substance and $\Delta T$ is the change in temperature.

The following is a list of the specific heat capacities of different substances.

http://en.wikipedia.org/wiki/Heat_capacity#Heat_capacity