Efficiency of LED light

Electricity and Magnetism Level 1

An incandescent light bulb, incandescent lamp or incandescent light globe is an electric light which produces light with a filament wire heated to a high temperature by an electric current passing through it, until it glows. An LED lamp is a light-emitting diode (LED) product that is assembled into a lamp (or light bulb) for use in lighting fixtures. If the efficiencies of an incandescent light bulb and an LED lamp are 8 8 % and 20 20 %, respectively, and the electric power consumption of the incandescent light bulb is 60 60 W, then what is the electric power consumption of the LED lamp with the same brightness?

24 W 6 W 12 W 32 W

Lakshan Dumpa by Lakshan Dumpa , 24, India

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2 solutions

Muzaffar Ahmed
Apr 2, 2014

By proportion, 60 × 8 / 20 = 24 60\times 8 / 20 = \boxed{24}

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Light Bulb = 60W, 8% Eff

LED Lamp = x W, 20% Eff

Let x = Power of LED Lamp

Since:

(LB EFF)(LB POW)=(LL EFF)(LL POW)

(8%/100%)(60W)=(20%/100%)(x)

{[(0.08)(60 W)]/(0.2)} = x

x, LL POW = 24W

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