If the two lamps marked 22V 200W and 220V 40W are connected in series and connected into the 380V circuit, they will burn down, After calculating the resistance, the 40W bulb will not be used

If the two lamps marked 22V 200W and 220V 40W are connected in series and connected into the 380V circuit, they will burn down, After calculating the resistance, the 40W bulb will not be used

The total resistance of series circuit is 1212.42; the current is 380 / 1212.42 = 0.31; so the voltage of lamp 22V is 0.7502v; the voltage of lamp 220V is 375.1v, which greatly exceeds the rated voltage of 220V, so 40W is burned

(Yangzhou, 2008) Xiaohong's mother bought a cheap desk lamp from the market. After installing a "220 V & nbsp; 25 W" bulb, when the plug was inserted into the socket of the home circuit, all the indoor lights went out immediately, probably because ()
A. Poor contact between plug and socket B. broken filament of bulb C. short circuit in socket of desk lamp D. open circuit in plug of desk lamp

Because the table lamp is connected in parallel with other electrical appliances, the plug is in poor contact with the socket, or the filament of the bulb is broken, it can only make the lamp (table lamp) of this branch not on, and can not make other lamps go out, so a and B are wrong; the lamp socket of the table lamp is short circuited, when the plug is inserted into the socket, if the switch is closed, the power supply will be short circuited, and the fuse will be blown out