Question

a 66.26 watt bulb emits radiations of wavelength 100nm. if only 60%of energy emitted in the form of radiations then the mumber of quanta emitted by the bulb per second is​

Answer 1

Answer:

$n=2\times 10^9$

Explanation:

We are given that

Power of bulb=66.26 w

Wavelength of radiations=100 nm=$100\times 10^{-9}$

Energy emitted in the form of radiations=60%

We have to find the number of quanta emitted by the bulb per second.

t=1 sec

Work=$power\times time$

Work done=$66.26\times 1=66.26 J$

60% of 66.26 J=$\frac{66.26\times 60}{100}=39.756 J$

We know that

$E=\frac{nhc}{\lambda}$

Where n=Number of quanta

h=Plank's constant=$6.626\times 10^{-34} J$

c=Speed of light

$\lambda$=Wavelength of radiations

Substitute the values then we get

$39.756=\frac{n\times 6.626\times 10^{-34}\times 3\times 10^8}{100\times 10^{-9}}$

$n=\frac{39.756\times 100\times 10^{-9}}{6.626\times 10^{-34}\times 3\times 10^8}$

$n=2\times 10^9$

Hence, the number of quanta emitted by bulb per seconds=$n=2\times 10^9$