A heat lamp produces 270 watts of power at a wavelength of

- A heat lamp produces 27.0 watts of power at a wavelength of 6.6 mu.m<?xml:namespace prefix = v ns = \"urn:schemas-microsoft-com:vml\" /> <?xml:namespace prefix = o ns = \"urn:schemas-microsoft-com:office:office\" /> .

How many photons are emitted per second? (1 watt= 1 j/s)

Express your answer using two significant figures.

Solution

let the number of photons be x.so,

energy of photon=hc/lambda

so,

x*hc/lambda=P

or x*6.636*10^-34*3*10^8/(6.6*10^-6) = 27

or x=8.95*10^20 photons pre swecond