Photon Theory of Light

If the energy of a photon is given as, $\text{E}=3.03\times {10}^{-19} \mathrm{J}$, then, the wavelength $\mathrm{(\lambda )}$ of the photon is

Sun gives light at the rate of $1400 {\mathrm{Wm}}^{-2}$ of the area perpendicular to the direction of the light. Assume ${\lambda }_{\left(sunlight\right)}=6000 \stackrel{°}{\mathrm{A}}$. Calculate the number of protons/sec arriving at $1 {\mathrm{m}}^2$ area at that part of the earth.

Which of the is n the property of photon?

A source of light of power$P$  is shown in figure. Find the force on the block placed in the path of the light rays. The surface of body on which the light beam is incident is having a reflection coefficient $a_r$= $0.7$ and absorption coefficient $a_a=0.3$

The equation $E=pc$ is valid

 

An LED is constructed from a p-n junction diode using $\mathrm{GaAs}$. The energy gap is $1.9 \mathrm{eV}$.The $\lambda$ of light emitted will be equal to

All photons present in a light beam of a particular frequency have: 

If the maximum kinetic energy of the photoelectron is $12$eV. Then, the maximum stopping potential will be-____.

Which of the following statements is NOT true?

It has been experimentally demonstrated that

Minimum energy of quanta is $x$ Joule, the select the possible energy of other quanta

The energy of a photon having wavelength $700\mathrm{nm}$ is: $\left(hc=1242 \mathrm{eV} \mathrm{nm}\right)$

The remote control of a TV emits infra-red light of wavelength $900\mathrm{nm}$. The TV detector is made of a semiconductor whose band gap is $x \mathrm{eV}$. The detector is shielded by a semiconductor optical filter whose band gap is $y \mathrm{eV}$. From the four options below, select the best option for the TV to function.

In a high energy experiment an electron and a positron are annihilated. The total energy of $1.02\times {10}^{10} \mathrm{eV}$ gives rise to two $\gamma$$-$ray photons, each having the same energy. What will be the wavelength associated with each photon?

A laser pointer has an output power of $1 \mathrm{mW}$ and emits light of wavelength $660 \mathrm{nm}$. What is the approximate number of photons it emits per second?

An electron in hydrogen atom makes a transition from a higher energy level to $n=1.$ In the process a photon is emitted that has a momentum of $5.5\times {10}^{27} \mathrm{kg} \mathrm{m} {\mathrm{s}}^{-1}$. What is the principal quantum number of the level from where the electron made the transition?

An electron and a photon have the same wavelength. If $P$ is the momentum of the electron and $E$ is the energy of the photon, then $E/p$ is

In a photoelectric effect experiment, a point source of light of power $3.2 \mathrm{mW}$ emits photons each of which has $5 \mathrm{eV}$ energy. The source is located at a distance of $0.8 \mathrm{m}$ from the centre of a stationary metal disk having a work function of $3 \mathrm{eV}.$ The metal disk has a radius of $8\times {10}^{-3} \mathrm{m}.$ Assuming that one photoelectron is emitted for every ${10}^6$ photons striking the surface of the disk, how many photoelectrons are emitted every second?

Calculate the force exerted on a small plane mirror by a plane electromagnetic wave of wave intensity $6 \mathrm{W} {\mathrm{m}}^{-2}$ which strikes the small mirror of area $40 {\mathrm{cm}}^2$ and the mirror is held perpendicular to the approaching wave.

Planck’s constant has the dimension of