(20 13? Jinhua) The picture shows a distributed photovoltaic power station built on the roof by a villager in Linhai City. This is the first photovoltaic power station connected to the grid in Zhejian

(20 13? Jinhua) The picture shows a distributed photovoltaic power station built on the roof by a villager in Linhai City. This is the first photovoltaic power station connected to the grid in Zhejiang Province. power station (1) given power P=5kW, time t=4h, according to W=Pt:

Daily output of photovoltaic power station W=Pt=5kW×4h=20kW? h.

(2) It is known that the rated voltage of the electric kettle is U =220V and the resistance R = 44Ω.

Then according to ohm's law:

Rated current of electric kettle I = U = R = 220V44ω = 5A

Rated power of electric kettle p = u i = 220v× 5a =1100w.

(3) The resistance of the electric kettle is constant. When the voltage at both ends decreases, according to P=U2R, the power decreases.

Answer: (1) The photovoltaic power station generates 20 kWh of electricity this day.

(2) The rated current of the electric kettle is 5A, and the rated power of the electric kettle is 1 100W.

(3) If the voltage at both ends of the electric kettle (with constant resistance) decreases, the power of the electric kettle decreases, because the resistance of the electric kettle remains unchanged. When the voltage at both ends decreases, the power decreases according to P=U2R.