Kettle advertising slogan

(1) v = 2.5l = 2.5x10-3m3?

According to the formula, the mass of this pot of water is obtained.

M = rho water V =1.0×103 kg/m3× 2.5×10-3 m3 = 2.5 kg;

The heat required to boil this pot of water.

Q absorption = cm (t-t0) = 4.2×103j/(kg℃ )× 2.5 kg× (100℃-20℃) = 8.4×105j;

(3) If all the electric energy consumed when boiling water is absorbed by water, then

W=Q suction =8.4× 10 5 J

According to the formula P=, it = 1200 s=20 minutes.

That is to say, it takes at least 20 minutes to boil this pot of water according to the power advertised by the electric kettle, and it is impossible to boil a pot of water in about 5 minutes. It can be seen that the content of publicity advertisements is not credible;

(4) the power of the electric kettle. Because the capacity and boiling time of the kettle can be accurately judged according to people's life experience, they are not familiar with the power of the electric kettle and it is not convenient to measure it directly.