A bulb emits light of wavelength 4500 mathri | vedclass

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(B) Given: Wavelength $\lambda = 4500 \ \mathring{A} = 4500 	imes 10^{-10} \ m = 4.5 	imes 10^{-7} \ m$. Power of bulb $P = 150 \ W = 150 \ J/s$. Ef

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$2.72 	imes 10^{19}$

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(B) Given: Wavelength $\lambda = 4500 \ \mathring{A} = 4500 	imes 10^{-10} \ m = 4.5 	imes 10^{-7} \ m$. Power of bulb $P = 150 \ W = 150 \ J/s$. Efficiency of light emission = $8 \ \%$. Energy emitted as light per second $E = 150 	imes \frac{8}{100} = 12 \ J/s$. Let $n$ be the number of photons emitted per second. The energy of one photon is $E_{photon} = \frac{hc}{\lambda}$. Total energy $E = n 	imes \frac{hc}{\lambda} \implies n = \frac{E \lambda}{hc}$. Substituting the values: $n = \frac{12 	imes 4.5 	imes 10^{-7}}{6.626 	imes 10^{-34} 	imes 3 	imes 10^8} \approx \frac{54 	imes 10^{-7}}{19.878 	imes 10^{-26}} \approx 2.716 	imes 10^{19}$. Thus,the number of photons is approximately $2.72 	imes 10^{19}$.

$A$ bulb emits light of wavelength $4500 \ \mathring{A}$. The bulb is rated at $150 \ W$ and $8 \ \%$ of the energy is emitted as light. What is the number of photons emitted by the bulb in $1 \ s$?

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