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Physics - W.E.P. Question with Solution | TestHub

PhysicsW.E.P.PowerEasy2 minPYQ_2020

PhysicsEasysingle choice

A $200 W$ sodium street lamp emits yellow light of wavelength $0.6 μ m .$ Assuming it to be $25 %$ efficient in converting electrical energy to light, the number of photons of yellow light emitted per second is

Options:

Answer:

Solution:

Efficient power $p = \frac{N}{t} \times \frac{h c}{λ} = 200 \times 0.25$

$\frac{N}{t} = 50 \times \frac{λ}{h c}$

$= \frac{50 \times 0.6 \times 10^{- 6}}{6.6 \times 10^{- 34} \times 3 \times 10^{8}}$

$= 1.5 \times 10^{20}$

Stream:NTA_ABHYAS_NEETSubject:PhysicsTopic:W.E.P.Subtopic:Power

⏱ 2mℹ️ Source: PYQ_2020

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