If there is no electric light, turn it off and on again, is this really an act of saving power 5

When it is just opened, because the filament temperature is low, so the resistance is relatively small, and the current is larger, according to P u 2 R, when you are unchanged, the smaller R P is, so the electric power is larger at the moment of opening, but only in an instant, so in fact, when it is turned on, it will not consume much more than the actual one, your physics teacher considers that the light bulb is easy to break when it is opened, if it is from the perspective of energy saving, the light can be turned off is always the most energy-saving.

Suppose a 1000w incandescent lamp is used 24 hours a day, and it uses 24 kWh of electricity, ask your waste wood teacher to turn on the incandescent lamp 4 times a day, 1 hour each time, and use 4 kWh of electricity a day. Do you say turning off the lights can save electricity? Your teacher said that the moment you turn on the incandescent lamp is 8 times the amount of electricity it uses to work normally, is it enough for 3 minutes when the light is turned on in his house?

How much more electricity will be used? Your teacher doesn't have any urine and is still teaching the next generation of the motherland, owed!

Your teacher is stupid. That's just a momentary increase in current. The principle of tungsten filament luminescence is that the temperature becomes high, and the filament enters the state in less than half a second after the light is turned on.

Because the switch has the highest current at the moment it is turned on, it can damage the bulb if it is turned on and off all the time.

The only benefit is that the extended life of the lamps and switches has nothing to do with energy savings.

You can call your principal to get your physics teacher out of class!

For power consumption, it must be on for a long time and consume electricity. Because the moment it is turned on, the current in the circuit is very large, and the power is also very large, but the time is very short, so the power consumed is not very large. It is recommended that if you don't use it for just one or two minutes, let it be left on, which will save power.

And the increased current at the start also causes a certain loss to the electrical appliances, so do not turn the electrical appliances on and off frequently. Every time it is opened, it will be cleared to reduce the service life, which is not conducive to the maintenance of the lamp, will increase the failure rate, and reduce the life.

Does it cost more electricity to turn lights on and off? Why?

Hello! If it is a bulb, it is a long time to ignite the electricity, the bulb filament is a heating resistance, you turn on and off does not affect the temperature of the filament, the resistance changes small, so its consumption such as collapse energy also changes small. However, if you light the rubber bucket for a long time, the resistance has been working, so the energy consumption is greater.

If it is an incandescent lamp, it is more power-consuming to open and off, its lamp is filled with a certain amount of argon and thin mercury vapor grinding gas, it needs to be excited in a short period of time under high temperature and high pressure, and it is excited to conduct light, this process is the most power-consuming, you always turn on and off, so you keep repeating this process, so it is the most power-consuming when you open and close.

Yes. Because the instantaneous current when the lamp is turned on and off is greater than the current when it is working normally, the instantaneous power is large.

To a certain extent, it makes sense.

Because 1, the changing current produces a changing magnetic field.

2. When the light of the lamp is lit, it is heated to a certain temperature by the filament to emit light, so when you turn off the light, the filament is cooled, and you turn on the light again, then you must reheat it to the temperature that is hot, so if you don't turn off the light, you will save electricity.

Of course, if you don't have the lights on for a while, then you need to turn off the lights.

If the starting current is ten times the operating current and it takes five seconds to start, then one start is equivalent to fifty seconds of operation. In fact, most electrical appliances do not have this high current when they start, and this is a long time. However, for some filament (cathode) emitting electronic appliances, such as fluorescent lamps, electron tubes, TV picture tubes, etc., the impact on the cathode life is equivalent to half to three hours of work at a start.

Therefore, these devices should be started as frequently as possible, that is, if they are only stopped for less than half an hour, they are not necessarily non-shutdown. But this is not from the perspective of energy saving, but from the perspective of extending the service life of the equipment.

It doesn't cost me to do electrical appliances, even if you keep turning on and off the lights, it's fine, which is much less than always leaving the lights on, but doing so has an impact on the life of the lights and switches.

Although the instantaneous current of turning on the light is large, its time is short, so short that it can be ignored, so if in order to save power, the light can be turned off, let him work less, and then turn it on when it is used. This is the most effective way to save electricity.

It makes sense because the instantaneous current when the lamp is turned on is greater than the current when it is working normally, so the instantaneous power is large

You can try that if the light in your house is quite close to the TV, there will be ripples on the TV when the light is turned on (this is what our teacher said, I didn't find) is the cause of magnetic interference.

To a certain extent, it makes sense, because 1, the changing current produces a changing magnetic field, 2, the light of the lamp is heated to a certain temperature by the filament, and it is glowing, so when you turn off the light, the filament cools, and you turn on the light again, then you must reheat to the temperature of the heat, so it is relatively different to every time you turn off the light, it will save electricity, of course, if you want to not light up for a while, then you have to turn off the light.