The energy of a quanta of frequency ${10}^{15}$ Hz and  will be:

1. $6.6×{10}^{-19}$ $\mathrm{J}$

$\mathrm{}$2.$6.6×{10}^{-12}$ $\mathrm{J}$

3. $6.6×{10}^{-49}$ $\mathrm{J}$

$\mathrm{}$4.$6.6×{10}^{-41}$ $\mathrm{J}$

Subtopic:  Particle Nature of Light |
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A helium-neon laser produces monochromatic light of a wavelength of 667 nm. The power emitted is 9 mW. The average number of photons arriving per second on average at a target irradiated by this beam is:

1. $9×{10}^{17}$

2. $3×{10}^{16}$

3. $9×{10}^{15}$

4. $3×{10}^{19}$

Subtopic:  Particle Nature of Light |
79%
From NCERT
NEET - 2009
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A source S1 is producing, 1015 photons per sec of wavelength 5000 Å. Another source S2 is producing 1.02×1015 photons per second of wavelength 5100 Å. Then the ratio of the power of S2 to the power of S1 is equal to:

 1 1 2 1.02 3 1.04 4 0.98
Subtopic:  Particle Nature of Light |
73%
From NCERT
AIPMT - 2010
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A 200 W sodium street lamp emits yellow light of wavelength 0.6 $\mathrm{\mu m}$. If it is 25% efficient in converting electrical energy to light, how many photons of yellow light does it emit per second?

1. $1.5×{10}^{20}$

2. $6×{10}^{18}$

3. $62×{10}^{20}$

4. $3×{10}^{19}$

Subtopic:  Particle Nature of Light |
70%
From NCERT
AIPMT - 2012
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