Question

A red bulb and violet bulb of equal power emits `n_(R )` and `n_(v)` number of photons in a given time, then
A. `n_(R ) = n_(v)`
B. `n_(R ) gt n_(v)`
C. `n_(R ) lt n_(v)`
D. `n_(R ) ge n_(v)`

Answer 1

Correct Answer - B
We know that, `E-(hc)/(lambda)`
Let, power=P
then, energy in time t
`nE=Pt" and "n=(Pt)/(E)=(Ptlambda)/(hc)`
`therefore" "n_(R)=(Ptlambda_(R))/(hc)" "...(i)`
`n_(v)=(Ptlambda_(v))/(hc)" "....(ii)`
Dividing Eq. (i) by Eq. (ii), we get
`(n_(R))/(n_(v))=(lambda_(R))/(lambda_(v))`
We know, `lambda_(R) gt lambda_(v)`
`n_(R) gt n_(V)`