Browse by Stream
QnA
Home
QnA
Go To Your Study Dashboard

Get Answers to all your Questions

header-bg qa

If \phi _1 \ \ and \ \phi _2 are the photon flux (\phi) due to a point isotropic source at a distance r and 2r from it respectively . then the ratio\frac{\phi _1 }{ \ \phi _2} is given as 

Option: 1

4


Option: 2

2


Option: 3

3


Option: 4

1


Answers (1)

best_answer

The photon flux (\phi) due to a point isotropic source at a distance r from it is given as

\phi = \frac{number \ of \ photon \ per \ sec }{surface \ area \ of \ sphere \ of \ radius \ r}=\frac{n}{4\pi r^2}

So \frac{\phi _1 }{ \ \phi _2}=\frac{r_2^2}{r_1^2}=(\frac{2r}{r})^2=4

Posted by

Rakesh

View full answer

JEE Main high-scoring chapters and topics

Study 40% syllabus and score up to 100% marks in JEE

Similar Questions