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JEE Mains · Physics · STD 12 - 11. Dual nature of radiation and matter
A Laser light of wavelength \(660\,nm\) is used to weld Retina detachment. If a Laser pulse of width \(60\, ms\) and power \(0.5\, kW\) is used the approximate number of photons in the pulse are : [Take Planck's constant \(h\, = 6.62\times10^{- 34}\, Js\)]
- A \(10^{20}\)
- B \(10^{18}\)
- C \(10^{22}\)
- D \(10^{19}\)
Answer & Solution
Correct Answer
(A) \(10^{20}\)
Step-by-step Solution
Detailed explanation
Given, \(\lambda=660 \mathrm{nm}, \text { Power }=0.5 \mathrm{kW}, \mathrm{t}=60 \mathrm{ms}\) Power \(P=\frac{\text { nhc }}{\lambda t} \Rightarrow n=\frac{p \lambda t}{h c}\) \(=0.5 \times 10^{3} \times \)…
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