Energy Carried by Electromagnetic Waves Video Lessons

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Problem: A light-emitting diode (LED) connected to a 3.0 V power supply emits 440 nm blue light. The current in the LED is 16mA, and the LED is 71% efficient at converting electric power input into light power output. How many photons per second does the LED emit?

FREE Expert Solution

Power and Energy relation:

P=Et

Electrical power:

P=Vi

The energy carried by electromagnetic wave:

E=hcλ

Efficiency:

η=PoutPin

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Problem Details

A light-emitting diode (LED) connected to a 3.0 V power supply emits 440 nm blue light. 

The current in the LED is 16mA, and the LED is 71% efficient at converting electric power input into light power output. 

How many photons per second does the LED emit?

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