The correct option is C 2.72×1019
Given,
the power of the bulb =150 watt=150 J s−1
So, the energy released by the bulb in the form of light per second =150×8100 J=12 J
Again, the wavelength of emitted light, λ=4500 ∘A
We know,
E=nhv=n×hcλ=Energy emitted by bulb in the form of light
Thus,
n×hc4500×10−10=12 J
⇒n×6.62×10−34×3×1084500×10−10=12 J
⇒n=2.72×1019