Question:medium
\(10^{20}\) photons of wavelength \(660\,\text{nm}\) are emitted per second from a lamp. The wattage of the lamp is (Planck’s constant \(h=6.6\times10^{-34}\,\text{Js}\))
\(10^{20}\) photons of wavelength \(660\,\text{nm}\) are emitted per second from a lamp. The wattage of the lamp is (Planck’s constant \(h=6.6\times10^{-34}\,\text{Js}\))
Show Hint
Photon power:
\begin{itemize}
\item Multiply energy per photon by photons/sec.
\end{itemize}
Updated On: Mar 2, 2026
- 30 W
- 60 W
- 100 W
- 500 W
Show Solution
The Correct Option is A
Solution and Explanation
Was this answer helpful?
0
Top Questions on Photoelectric Effect
- Light is incident on a metallic plate having work function \(110 \times 10^{-20}\,\text{J}\). If the produced photoelectrons have zero kinetic energy, then the angular frequency of the incident light is _________ rad/s. (\(h = 6.63 \times 10^{-34}\,\text{J·s}\))}
- JEE Main - 2026
- Physics
- Photoelectric Effect
- When a light of a given wavelength falls on a metallic surface the stopping potential for photoelectrons is \(3.2\ \text{V}\). If a second light having wavelength twice of the first light is used, the stopping potential drops to \(0.7\ \text{V}\). The wavelength of the first light is ________ m.
- JEE Main - 2026
- Physics
- Photoelectric Effect
- Assertion : Photoelectric effect is a spontaneous phenomenon. Reason (R): According to the wave picture of radiation, an electron would take hours/days to absorb sufficient energy to overcome the work function and come out from a metal surface.
- CBSE Class XII - 2026
- Physics
- Photoelectric Effect
- Light of which of the following colours will have the maximum energy in a photon associated with it?
- CBSE Class XII - 2026
- Physics
- Photoelectric Effect
- Want to practice more? Try solving extra ecology questions todayView All Questions
Questions Asked in WBJEE exam
Manufacturers supply a zener diode with zener voltage \( V_z=5.6\,\text{V} \) and maximum power dissipation \( P_{\max}=\frac14\,\text{W} \). This zener diode is used in the circuit shown. Calculate the minimum value of the resistance \( R_s \) so that the zener diode will not burn when the input voltage is \( V_{in}=10\,\text{V} \). 
- WBJEE - 2026
- Zener Diodes
Two charges \( +q \) and \( -q \) are placed at points \( A \) and \( B \) respectively which are at a distance \( 2L \) apart. \( C \) is the midpoint of \( AB \). The work done in moving a charge \( +Q \) along the semicircle CSD (\( W_1 \)) and along the line CBD (\( W_2 \)) are 
- WBJEE - 2026
- electrostatic potential and capacitance
