A 100 watt bulb emits monochromatic light of wavelength 400 nm. Calculate the number of photons emitted per second by the bulb.

Question

A 100 watt bulb emits monochromatic light of wavelength 400 nm. Calculate the number of photons emitted per second by the bulb. (A) 3 × 1020 s-1 (B) 2 × 10-20 s-1 (C) 2 × 1020 s-1 (D) 1 × 10-20 s-1

Tardigrade Admin · Accepted Answer

Power of the bulb = 100 watt = 100 J s-1 Energy of one photon E = h upsilon = hc/λ =(6.626 × 10-34 J s × 3 × 108 m s-1/400 × 10-9 m) =4.969×10-19 J Number of photons emitted =(100 J s-1/4.969 × 10-19 J) =2.012×1020 s-1

Q. A $100$ watt bulb emits monochromatic light of wavelength $400 nm$ . Calculate the number of photons emitted per second by the bulb.

$3 \times 1 0^{20} s^{- 1}$

$2 \times 1 0^{- 20} s^{- 1}$

$2 \times 1 0^{20} s^{- 1}$

$1 \times 1 0^{- 20} s^{- 1}$

Q. A 100 watt bulb emits monochromatic light of wavelength 400nm. Calculate the number of photons emitted per second by the bulb.

3×1020s−1

2×10−20s−1

2×1020s−1

1×10−20s−1

Power of the bulb =100 watt =100Js−1 Energy of one photon E=hυ=hc/λ =400×10−9m6.626×10−34Js×3×108ms−1​ =4.969×10−19J Number of photons emitted =4.969×10−19J100Js−1​ =2.012×1020s−1

Q. A $100$ watt bulb emits monochromatic light of wavelength $400 nm$ . Calculate the number of photons emitted per second by the bulb.

$3 \times 1 0^{20} s^{- 1}$

$2 \times 1 0^{- 20} s^{- 1}$

$2 \times 1 0^{20} s^{- 1}$

$1 \times 1 0^{- 20} s^{- 1}$