WBJEE · Physics · Dual Nature of Matter
\(10^{20}\) photons of wavelength 660 nm are emitted per second from a lamp. The wattage of the lamp is (Planck's constant \(\left.=6.6 \times 10^{-34} \mathrm{Js}\right)\)
- A 30W
- B 60W
- C 100W
- D 500W
Answer & Solution
Correct Answer
(A) 30W
Step-by-step Solution
Detailed explanation
\(P=N\left(\frac{h c}{\lambda}\right)\) \(\mathrm{P}=10^{20} \times \frac{6.6 \times 10^{-34} \times 3 \times 10^8}{660 \times 10^{-9}}=30 \mathrm{~W}\)
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