# A source $S_{1}$ is producing, $10^{15}$ photons per second of wavelength 5000 $A^{\circ}$. Another source $S_{2}$ is producing $1.02\times 10^{15}$ photons per second of wavelength 5100 $A^{\circ}$ Then, (power of $S_{2}$) (power of $S_{1}$) is equal to: Option 1) 1.00 Option 2) 1.02 Option 3) 1.04 Option 4) 0.98

D Divya Saini

As we discussed in concept

photon -

A packet or bundle of energy is called a photon

-

and

Energy of a photon -

$\fn_jvn E= h\nu = \frac{hc}{\lambda }$

- wherein

$\fn_jvn h= Plank's\: constant$

$\boldsymbol{\nu= frequency\: of \: radiation }$

$\fn_jvn \lambda \rightarrow wave \: length$

Power = $N\:=\frac{hc}{\lambda}$

$\frac{P_{2}}{P_{1}}=\frac{\frac{N_{1}}{\lambda_{1}}}{\frac{N_{2}}{\lambda_{2}}}\:=\: \frac{N_{2} \lambda_{2}}{N_{2} \lambda_{1}} = \frac{10^{15}\times 5100\times 10^{-10}}{1.02\times 10^{15}\times 5000\times 10^{10}}$

$\frac{P_{2}}{P_{1}}\:=\:\frac{5100}{5100}\:=\:1$

Option 1)

1.00

This option is correct.

Option 2)

1.02

This option is incorrect.

Option 3)

1.04

This option is incorrect.

Option 4)

0.98

This option is incorrect.

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