In order to make the "6V & nbsp; 3W" bulb connect to 8V power supply to light normally, what resistance should be connected in series?

In order to make the "6V & nbsp; 3W" bulb connect to 8V power supply to light normally, what resistance should be connected in series?

Rated voltage of bulb: u = 6V; rated power: P = 3W; then the rated current of bulb: I = Pu = 3w6v = 0.5A; voltage at both ends of series resistance: ur = U-U = 8v-6v = 2V; so the resistance of series resistance: r = URI = 2v0.5a = 4 Ω; answer: the resistance of series resistance should be 4 Ω

The rated power of 1 ohm and 2 ohm resistors is 0.5W. After series connection, under the condition of not exceeding the rated power loss, how much V can the maximum voltage be added?

The resistance of 1.5V and 2 ohm will be broken

The resistance duty r of a resistance element is 1K Ω, and the rated power PN is 2.5W?
（A）2.5V （B）250V （C）50V

P=UI=U^2/R =>
U=√(P*R)
=√(2.5*1000)
=50V
The answer is: C