Physics · 2012
NEET 2012 · Prelims · Code A · Q41
A 200 W sodium street lamp emits yellow light of wavelength 0.6 μ m. Assuming it to be 25% efficient in converting electrical energy to light, the…
A $\displaystyle 200$ W sodium street lamp emits yellow light of wavelength $\displaystyle 0.6 \mu \mathrm{~m}$. Assuming it to be $\displaystyle 25$% efficient in converting electrical energy to light, the number of photons of yellow light it emits per second is :
Official answer
(3)
$\displaystyle 1.5 \times 10^{20}$
More from Dual Nature of Radiation and Matter
- Photons with energy 5 eV are incident on a cathode C in a photoelectric cell. The maximum energy of emitted photoelectrons is 2 eV. When photons of…2016
- If c is the velocity of light in free space, the correct statements about photon among the following are: A. The energy of a photon is E=h v. B. The…2024
- An electron is accelerated from rest through a potential difference of V volt. If the de Broglie wavelength of the electron is 1.227 × 10^-2 nm, the…2020
- A photon and an electron (mass m ) have the same energy E. The ratio ( λ_photon / λ_electron ) of their de Broglie wavelengths is: ( c is the speed…2025
- When the energy of the incident radiation is increased by 20\%, the kinetic energy of the photoelectrons emitted from a metal surface increased from…2014
- The number of photons per second on an average emitted by the source of monochromatic light of wavelength 600 nm, when it delivers the power of 3.3 ×…2021
- An electron is accelerated through a potential difference of 10,000 V. Its de Broglie wavelength is, (nearly): (m_e=9 × 10^-31 kg)2019
- For a metal of work function 6.6 eV, which of the following wavelengths of incident radiation does not give rise to the photoelectric effect? (Take…2026
NEET (UG) 2012 Physics question, with the answer from NTA’s final answer key. Where our answers come from.