How many photons are emitted by a laser source of 5 × 10 - 3 W operating at 632 . 2 nm in 2 s ?

The energy of each photon E 0 = h c λ = 6.63 × 10 - 34 × 3 × 10 8 632.2 × 10 - 9 = 3.15 × 10 - 19 J Total energy = E = P t ∴ n E 0 = P t ⇒ n = P t E 0 = 5 × 10 - 3 × 2 3.15 × 10 - 19 = 3.2 × 10 16

Start Free Mock LoginAlready registered? Login here

Physics - Modern Physics Question with Solution | TestHub

PhysicsModern PhysicsPhotoelectric effectEasy2 minPYQ_2020

PhysicsEasysingle choice

How many photons are emitted by a laser source of $5 \times 10^{- 3} W$ operating at $632.2 nm$ in $2 s$ ?

Options:

Answer:

Solution:

The energy of each photon

$E_{0} = \frac{h c}{λ} = \frac{6.63 \times 10^{- 34} \times 3 \times 10^{8}}{632.2 \times 10^{- 9}} = 3.15 \times 10^{- 19} J$

Total energy $= E = P t$

$∴ n E_{0} = P t$

$\Rightarrow n = \frac{P t}{E_{0}} = \frac{5 \times 10^{- 3} \times 2}{3.15 \times 10^{- 19}} = 3.2 \times 10^{16}$

Stream:NTA_ABHYAS_NEETSubject:PhysicsTopic:Modern PhysicsSubtopic:Photoelectric effect

⏱ 2mℹ️ Source: PYQ_2020

Doubts & Discussion

Loading discussions...