A monochromatic source of light operating at 15 kW emits photons/s. The region of an electromagnetic spectrum

Question

A monochromatic source of light operating at 15 kW emits $2.5 \times 10^{22}$ photons/s. The region of an electromagnetic spectrum to which the emitted electromagnetic radiation belongs to ______.

(Take $h = 6.6 \times 10^{- 34} J . s$ and $c = 3 \times 10^{8} m / s$ ). [2026]

Smart Achievers · Accepted Answer

(4)

$Power P = \frac{n h c}{λ}; n are numbers of photons emitted per second$

$\Rightarrow λ = \frac{n h c}{P}$

$λ = \frac{2.5 \times 10^{22} \times 6.6 \times 10^{- 34} \times 3 \times 10^{8}}{15 \times 10^{3}}$

$λ = 3.3 \times 10^{- 7} m = 3300 Å$

$Ultraviolet light, lies in this wavelength range.$

Solution

Q.
A monochromatic source of light operating at 15 kW emits $2.5 \times 10^{22}$ photons/s. The region of an electromagnetic spectrum to which the emitted electromagnetic radiation belongs to ______.

(Take $h = 6.6 \times 10^{- 34} J . s$ and $c = 3 \times 10^{8} m / s$ ). [2026]

1 Microwave

2 Infrared

3 Visible

4 Ultraviolet

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