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

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=P t ∴ n E0=P t ⇒ n=(P t/Eo) =(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

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=Eo​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 $2 s$ ?

$3.2 \times 1 0^{16}$

$1.6 \times 1 0^{16}$

$4 \times 1 0^{16}$