The word "220 V, 40 W" is marked on the white woven lamp. 220 V indicates the voltage of the light bulb, called. Voltage, 40 W. the electric power of the light bulb is called power

The word "220 V, 40 W" is marked on the white woven lamp. 220 V indicates the voltage of the light bulb, called. Voltage, 40 W. the electric power of the light bulb is called power

normal
rated
Rated voltage
rated

One day, Xiao Ming noticed that the light bulb in his home was brighter than usual. He guessed that the voltage might exceed 220 v. in order to confirm his conjecture, he did the following experiments: turn off other household appliances, turn on only one "220 V & nbsp; & nbsp; 100 W" electric light, and observe that the electric energy meter marked with "3000 R / kWh" in his home turns 121 times in 20 minutes. (1) what's the resistance of this lamp? (excluding the influence of temperature on filament resistance) (2) what is the power consumption of this lamp in 20 minutes? (3) What is the actual voltage of Xiaoming's house at this time? (4) In order to make the lamp work normally, what resistance should be connected in series?

(1) The resistance of this lamp is r = u2p = (220V) 2100W = 484 Ω. (2) the electric energy consumed by this lamp in 20 minutes is w = 1213000kw · H = 1213000 × 3.6 × 106j = 1.452 × 105J. (3) the actual power is p = wt = 1.452 × 105j20 × 60s = 121w

What is the actual electric power of a "220 V, 15 W" bulb with 220 V and 110 V applied at both ends?

It is known that the rated voltage of the bulb is 220 V, the rated power is 15 W, the resistance value of the bulb: & nbsp; r = u, 2p = (220 V) 215 w ≈ 3226.7 Ω; when the actual voltage U1 = 220 V, the actual voltage is equal to the rated voltage, the actual power of the bulb: P1 = P, 2p = 15 W; when the actual voltage U2 = 110 V, the actual power of the bulb: P = u

If the two lamps marked with "220 V, 40 W" and "220 V, 15 W" are connected in series under 220 V voltage, the following analysis is correct ()
A. The total power of the two lamps is equal to 55wb. The total power of the two lamps is less than 15wc. The actual power of lamp a is greater than that of lamp B. the actual power of lamp B is greater than that of lamp a

The power of the two lamps is not the rated power, so the total power is not the sum of the rated power of the two lamps, so a is wrong; R1 = u21p1 = (220 V) 240W = 1210 Ω for "220 V, 40 W" lamp a; R2 = u22p2 = (220 V) 215W = 3226.7 Ω for "220 V, 15 W" lamp B; because the series current is equal, the resistance of lamp a is small