A 100 W sodium lamp radiates energy uniformly in all directions. lamp is located at centre of a larg

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11.Dual Nature of Radiation and matter

easy

A $100 \;W$ sodium lamp radiates energy uniformly in all directions. The lamp is located at the centre of a large sphere that absorbs all the sodium light which is incident on it. The wavelength of the sodium light is $589\; nm$.

$(a)$ What is the energy per photon associated with the sodium light?

$(b)$ At what rate are the photons delivered to the sphere?

Option A

Option B

Option C

Option D

Solution

$P =100 \,W$

$\lambda=589 \,nm$

$(a)$ Energy per photon $=h c / \lambda$ $=3.37 \times 10^{-19} \,J$

$(b)$ No. of photons per $= P / E$ $=3 \times 10^{20}$ Photons/ second

Standard 12

Physics

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