What does 10 (20) a mean on an energy meter?

What does 10 (20) a mean on an energy meter?

Rated current 10 A
Fuse current 20 A

A classmate has an electric energy meter marked with "220 V 2.5 (10) a 1500 R / kW · H". He takes a light bulb and an electric energy meter at home
A classmate has an electric energy meter, which is marked with "220 V 2.5 (10) a 1500 R / kW · H". After connecting a light bulb with the electric energy meter in the home lighting circuit, he closed the switch, and the light bulb glowed normally. He found that the aluminum disc in the middle of the electric energy meter rotated 10 times in 4 minutes. Please calculate the energy consumption when the light bulb glowed normally for 1 hour?

It is known that: 1500r / kW ` h 1kW '= 3.6x10 cubic J, so the work done by 1R = 360000j / 1500r = 2400j, because r = 10, so the work done by the bulb = 2400j / rx10r = 24000j, because the work time = 4 minutes = 360s, so the power of the lamp = P / T = 24000j / 360s = 66.7w, so the power consumed by the bulb is

Electrical problem: a classmate checked his own electric energy meter, which was marked with 3600r / kW. H, then he turned off all the electrical appliances in his home, only one was marked with 220V
The 1210w electric kettle works continuously. At the same time, it is observed that the turntable of the electric energy meter turns 180 in three minutes?
It's best to write a detailed thought. I already know the answer

W = 180r / 3600r * 1kW. H = 0.05kw. H = 1.8x10 ^ 5J
According to the rated voltage and power, r = 40 ohm
P actual = 1.8x10 ^ 5 / 180s = 1000W
So u actual = (1000x40) square root = 200V
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