Now calculate the heat loss rate due to radiation from a cylindrical cup containing 250mL of black coffee at 80C.  

Give your answer in Watts.

How many seconds does it take for the coffee to cool to 75C if heat is lost only by radiation?

You happen to put your coffee cup down on a set of scales, and notice that over 10

We want to estimate the heat loss rate due to radiation from a cylindrical cup containing 250mL of black coffee at 80C.  

The inside diameter of the cup is 80mm and it is made of black paper.  

First, calculate the surface area through which energy will be radiated - assume the bottom of the cup is insulated, but radiation occurs through the sides and open top

Give your answer in m²

Match the situations to the (primary) heat transfer mechanism at work

Thinking about the lab, which of the following might have posed problems in your attempts to measure the heat capacity of water?

If in part A a group simply opted for the following method:

1. pour 100g water into kettle
2. measure initial temp of water in the kettle
3. remove thermometer
4. simultaneously turn power on and note the power draw of the kettle
5. wait two minutes
6. at the two minute mark: simultaneously turn power off and measure final temperature of water

which of the following might be useful improvements to the method that should improve the quality of results? (Select all that apply)

If the kettle has a power rating of 2000W, how long (in seconds) will it take to boil the kettle?

Does this seem about right?

How does the energy required to heat the aluminium compare to heating water? Suggest a reason why.

You put just enough water in your electric kettle to make a cup of tea (raise the temperature from 20°C to 100°C). How much energy, in kJ, does this require?

Assume 1 cup = 250 ml, the density of water is 1 kg/L, and that the heat capacity of water is  4184 J kg^-1 K^-1