Ask Questions, Get Answers

Want to ask us a question? Click here
Browse Questions
0 votes

A bulb emits light of $\lambda=4500A^{\circ}$ .The bulb is rated as 150watt and 8% of the energy is emitted as light.How many photons are emitted by the bulb per second?

$\begin{array}{1 1}(a)\;37.5\times 10^{18}&(b)\;28.6\times 10^{12}\\(c)\;27.2\times 10^{18}&(d)\;32.3\times 10^{14}\end{array}$

Can you answer this question?

1 Answer

0 votes
Energy of one photon =$\large\frac{hc}{\lambda}$
$\Rightarrow \large\frac{6.625\times 10^{-34}\times 3\times 10^8}{4500\times 10^{-10}}$
$\Rightarrow 4.42\times 10^{-19}J$
Energy emitted by bulb=$150\times \large\frac{8}{100}$J
$\therefore n\times 4.42\times 10^{-19}=150\times \large\frac{8}{100}$
(n is no of photon)
$n=27.2\times 10^{18}$
Hence (c) is the correct answer.
answered Jan 15, 2014 by sreemathi.v

Related questions

Ask Question
student study plans
JEE MAIN, CBSE, NEET Mobile and Tablet App
The ultimate mobile app to help you crack your examinations
Get the Android App