A 100 watt bulb emits monochromatic light of wavelength 400 mathrmnm. The number of photons emitted by the bulb per second is

Question

A 100 watt bulb emits monochromatic light of wavelength 400 mathrmnm. The number of photons emitted by the bulb per second is (A) 2 × 1010 mathrm~s-1 (B) 2 × 1020 mathrm~s-1 (C) 3 × 1010 mathrm~s-1 (D) 3 × 1020 mathrm~s-1

Tardigrade Admin · Accepted Answer

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

Q. A $100 w a tt$ bulb emits monochromatic light of wavelength $400 nm$ . The number of photons emitted by the bulb per second is

$2 \times 1 0^{10} s^{- 1}$

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

$3 \times 1 0^{10} s^{- 1}$

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

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

2×1010 s−1

2×1020 s−1

3×1010 s−1

3×1020 s−1

Power of the bulb =100 watt =100 J s−1 Energy of one photon E=hv=hc/λ =400×10−9 m6.626×10−34 J s××3×108 m s−1​ =4.969×10−19 J Number of photons emitted =4.969×10−19 J100 J s−1​ =2.012×1020 s−1

Q. A $100 w a tt$ bulb emits monochromatic light of wavelength $400 nm$ . The number of photons emitted by the bulb per second is

$2 \times 1 0^{10} s^{- 1}$

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

$3 \times 1 0^{10} s^{- 1}$

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