A parallel beam of light of wavelength $900\,nm$ and intensity $100\,Wm ^{-2}$ is incident on a surface perpendicular to the beam. Tire number of photons crossing $1\,cm ^{2}$ area perpendicular to the beam in one second is :
A parallel beam of light of wavelength $900\,nm$ and intensity $100\,Wm ^{-2}$ is incident on a surface perpendicular to the beam. Tire number of photons crossing $1\,cm ^{2}$ area perpendicular to the beam in one second is :
- [JEE MAIN 2022]
- A
$3 \times 10^{16}$
- B
$4.5 \times 10^{16}$
- C
$4.5 \times 10^{17}$
- D
$4.5 \times 10^{20}$
Similar Questions
The continuous part of $X$-ray spectrum is a result of the
The continuous part of $X$-ray spectrum is a result of the
- [KVPY 2016]
The energy of a photon of light of wavelength $450 nm$ is
The energy of a photon of light of wavelength $450 nm$ is
A radio transmitter operates at a frequency of $880 \,kHz$ and a power of $10\,kW$. The number of photons emitted per second are
A radio transmitter operates at a frequency of $880 \,kHz$ and a power of $10\,kW$. The number of photons emitted per second are
- [AIPMT 1990]
One day on a spacecraft corresponds to $2$ days on the earth. The speed of the spacecraft relative to the earth is
One day on a spacecraft corresponds to $2$ days on the earth. The speed of the spacecraft relative to the earth is
A small object at rest, absorbs a light pulse of power $20\,mW$ and duration $300\,ns$. Assuming speed of light as $3 \times 10^8\,m / s$. the momentum of the object becomes equal to $.........\times 10^{-17} kg\,m / s$
A small object at rest, absorbs a light pulse of power $20\,mW$ and duration $300\,ns$. Assuming speed of light as $3 \times 10^8\,m / s$. the momentum of the object becomes equal to $.........\times 10^{-17} kg\,m / s$
- [JEE MAIN 2023]