Why is 11W energy saving lamp as bright as 60W white lamp

Why is 11W energy saving lamp as bright as 60W white lamp

A: the brightness of the two lamps is the same, which means that the current flowing through each lamp is equal. From P = UI = (U squared) / r = (I squared) r, ∵ P1 = 11W < P2 = 60W, I1 = I2 ∵ P1: P2 = (I1 squared) R1: (I2 squared) R2 = R1: R2 ∵ P1: P2 = 11 / 12 < 1 ∵ R1 < R2, from the heating power of resistance P = (I squared) r, ∵ 11W

Why is the "220 V 60 W" energy saving lamp brighter than the "220 V 60 W" incandescent lamp?

Electric light conversion efficiency is higher, called energy saving lamp
Therefore, the power consumption is the actual luminous power of 60W energy-saving lamp - the useful power is higher than that of ordinary bulb
To be more precise, the power consumption is 60W, the light power of energy-saving lamp may be 25W, while the light power of ordinary incandescent lamp may be only 10W
----Note that the power marked on the appliance is the total power consumed, not the useful power. Most incandescent lamps convert electric energy into heat energy

Why is the lighting effect of a kind of high efficiency energy-saving lamp marked with "220V 11W" equivalent to that of "220V 60W" incandescent lamp? Their electric power is not different?

Of course, the power is different, one is 11W, and the other is 60W. But their luminous mechanism is different. Incandescent lamps emit light by thermal radiation, while energy-saving lamps emit light by gas discharge. It's like a red iron block and a lighted match. If they emit the same heat, the match must be brighter. It's basically the same truth!

The circuit voltage of xiaomingjia is 220 V, and the maximum current allowed by the wire is 30 a
(1) If a "220 V 72 kW" electric water heater and a "220 V 2.8 kW" electric heater are used at the same time, their total power will be_______ , exceeding the maximum power allowed by the line
(2) It is known that the calorific value of natural gas is 8.0 × 107j / m3. If a 7.2kw electric water heater is replaced by a natural gas water heater_______ The energy released by the complete combustion of M3 natural gas is equal to that consumed by the electric water heater for 30s
. good answer, I'll add points.)

The maximum power allowed on the line is 220V * 30A = 6600w = 6.6kw