How many photons are emitted by a laser source of 5× 10- 3 W operating at 632.2 nm in 2 s ?

Question

How many photons are emitted by a laser source of 5× 10- 3 W operating at 632.2 nm in 2 s ? (A) 3.2× 1016 (B) 1.6× 1016 (C) 4× 1016 (D) None of these

Tardigrade Admin · Accepted Answer

The energy of each photon E0=(h c/λ )=(6.63 × 10- 34 × 3 × 108/632.2 × 10- 9)=3.15× 10- 19 J Total energy =E=Pt ∴ nE0=Pt ⇒ n=(P t/E0)=(5 × 10- 3 × 2/3.15 × 10- 19)=3.2× 1016

Q. How many photons are emitted by a laser source of $5 \times 1 0^{- 3} W$ operating at $632.2 nm$ in $2 s$ ?

$3.2 \times 1 0^{16}$

$1.6 \times 1 0^{16}$

$4 \times 1 0^{16}$

None of these

Q. How many photons are emitted by a laser source of 5×10−3W operating at 632.2nm in 2s ?

3.2×1016

1.6×1016

4×1016

None of these

The energy of each photon E0​=λhc​=632.2×10−96.63×10−34×3×108​=3.15×10−19J Total energy =E=Pt ∴nE0​=Pt ⇒n=E0​Pt​=3.15×10−195×10−3×2​=3.2×1016

Q. How many photons are emitted by a laser source of $5 \times 1 0^{- 3} W$ operating at $632.2 nm$ in $2 s$ ?

$3.2 \times 1 0^{16}$

$1.6 \times 1 0^{16}$

$4 \times 1 0^{16}$