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

Calculate the energy required, in kJ, to raise the temperature of a 0.25 kg block of aluminium from 20°C to 100°C.

Take the specific heat capacity of aluminium to be  904 J kg^-1 K^-1

What are the SI units of the specific heat capacity?

What is the main mechanism for heat transfer in the following siutation:

   Using a very bright lamp in a zoo to provide a warm area for animals in their enclosure

What is the main mechanism for heat transfer in the following siutation:

   Cooling a sports injury by placing an icepack over the bruised area.

Como é definido “seccionamento” na instalação elétrica?

Uma bateria de tem resistência interna de .

Assinale a opção que indica o valor da sua corrente de curto-circuito, em ampères.

Aparelho destinado a medir e avaliar grandezas elétricas: