a 100 watt bulb emits mono chromatic light of wavelenth 400 nm calculate the no. of photons emitted per second by the bulb

Asked by patidarshm | 11th Dec, 2015, 12:01: PM

Expert Answer:

begin mathsize 11px style Given colon Power space of space the space bulb space equals space 100 watt space equals space Work over Time space equals space 100 space straight J divided by straight s Energy space of space one space photon space equals space straight E space equals space straight h space straight c over straight lambda Where comma straight h space equals space 6.626 space cross times space 10 to the power of negative 34 end exponent space Js straight c space equals space 3 space cross times space 10 to the power of 8 space straight m divided by straight s straight lambda space equals space 400 space cross times space 10 to the power of negative 9 end exponent space straight m space Therefore comma space substituting space the space values space in space the space above space formula space we space get comma straight E space equals space fraction numerator 6.626 space cross times space 10 to the power of negative 34 end exponent space Js space cross times space 3.0 space cross times space 10 to the power of 8 space end exponent ms to the power of negative 1 space end exponent over denominator 400 space cross times space 10 to the power of negative 9 space end exponent straight m end fraction space space space equals space 4.969 space cross times space 10 to the power of negative 19 end exponent space straight J Number space of space photons space emitted space per space second space equals space fraction numerator 100 straight J divided by straight s over denominator 4.969 space cross times space 10 to the power of negative 19 end exponent space straight J end fraction space equals space bold 2 bold. bold 012 bold space bold cross times bold space bold 10 to the power of bold 20 bold space end exponent bold s to the power of bold minus bold 1 end exponent end style

Answered by Hanisha Vyas | 11th Dec, 2015, 06:25: PM