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A 600 W mercury lamp emits monochromatic...

A 600 W mercury lamp emits monochromatic radiation of wavelength 331.3 nm. How many photons are emitted from the lamp per second ? (`h = 6.626 xx 10^(-34)` Js, velocity of light `= 3 xx 10^(8) ms^(-1)`)

A

`1 xx 10^(19)`

B

`1 xx 10^(20)`

C

`1 xx 10^(21)`

D

`1 xx 10^(23)`

Text Solution

Verified by Experts

The correct Answer is:
C
Given, power = 600 W
`lambda = 331.3 nm = 331.3 xx 10^(-9)m`
`h = 6.626 xx 10^(-34) J`
`c = 3 xx 10^(8) ms^(-1)`
`t = 1s`
Power `= ("energy")/("time")`
`= (n h v)/(t) = (n h c)/(lambda t)`
or `n = ("power" xx lambda t)/(h c)`
`= (600 xx 331.3 xx 10^(-9) xx 1)/(6.626 xx 10^(-34) xx 3 xx 10^(8))`
`n = 1 xx 10^(21)`
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