(a) 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 of a large sphere , that absorbs all the sodium light which is incident on it . The wavelength of the sodium light is 589 nm (i) What is the energy associated per photon with the sodium light ? (ii) At what rate are the photons delivered to the sphere ?
(b) Light of frequency `7.21 xx10^(14)` Hz is incident on a metal surface . Electrons with a maximum speed of `6.0xx10^(5) ms^(-1)` are ejected from the surface What is the threshold frequency for photo emission of electron ?
Given , `h= 6.63xx10^(-34) Js , m_c=9.1xx10^(-310 Kg`

Explanation

### Step-by-Step Solution

#### Part (a)

**(i) Energy associated per photon with sodium light:**

1. **Given Data:**
- Power of the sodium lamp, \( P = 100 \, \text{W} \)
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