An electron and a photon each have a wavelength of 1.00 nm. The momentum of the electron will be:

(1) Greater than photon.

(2) Equal to the photon.

(3) Less than photon.

(4) None of these.
 

The work function of cesium metal is 2.14 eV. When light of frequency 6 × 10¹⁴ Hz is incident on the metal surface, photoemission of electrons occurs. What is the stopping potential of the metal?

(1) 0.212 V

(2) 0.345 V

(3) 0.127 V

(4) 0.311 V

The photoelectric cut-off voltage in a certain experiment is 1.5 V. What is the maximum kinetic energy of photoelectrons emitted?

$$\begin{gathered} \left(1\right) 2.1\times {10}^{-19} J \\ \left(2\right) 1.7\times {10}^{-19} J \\ \left(3\right) 2.4\times {10}^{-19} J \\ \left(4\right) 1.1\times {10}^{-19} J \end{gathered}$$

Monochromatic light of wavelength 632.8 nm is produced by a
helium-neon laser. The power emitted is 9.42 mW. The energy of each photon in the light beam is:

$$\begin{gathered} \left(1\right) 4.801\times {10}^{-19} J \\ \left(2\right) 2.121\times {10}^{-19} J \\ \left(3\right) 5.043\times {10}^{-19} J \\ \left(4\right) 3.141\times {10}^{-19} J \end{gathered}$$

The energy flux of sunlight reaching the surface of the earth is 1.388 × 10³ W/m². How many photons(nearly) per square meter are incident on the Earth per second? Assume an average wavelength of 550 nm.

(1) $3.84\times {10}^{21}$

(2) $2.97\times {10}^{21}$

(3) $4.12\times {10}^{21}$

(4) $2.10\times {10}^{21}$

In an experiment on the photoelectric effect, the slope of the cut-off voltage versus frequency of incident light is found to be $4.12\times {10}^{-15} V s$. The value of Planck's constant is:

(1) $6.682\times {10}^{-4} Js$

(2) $6.592\times {10}^{-34} Js$

(3) $6.621\times {10}^{-34} Js$

(4) $6.502\times {10}^{-4} Js$

A 100 W sodium lamp radiates energy uniformly in all directions. The lamp is located at the center of a large sphere that absorbs all the sodium light which is incident on it. The wavelength of sodium light is 589 nm. What is the energy per photon associated with the sodium light?

$$\begin{gathered} \left(1\right) 1.21 eV \\ \left(2\right) 2.21 eV \\ \left(3\right) 2.11 eV \\ \left(4\right) 1.11 eV \end{gathered}$$

Light of frequency $7.21\times {10}^{14} \mathrm{Hz}$ is incident on a metal surface. Electrons with a maximum speed of $6.0\times {10}^5 \mathrm{m}/\mathrm{s}$ are ejected from the surface. What is the threshold frequency for the photoemission of electrons?

$$\begin{gathered} \left(1\right) 5.109\times {10}^{14} Hz \\ \left(2\right) 3.345\times {10}^{14} Hz \\ \left(3\right) 6.733\times {10}^{14} Hz \\ \left(4\right) 4.738\times {10}^{14} Hz \end{gathered}$$

The threshold frequency for a certain metal is $3.3\times {10}^{14} \mathrm{Hz}.$ If the light of frequency $8.2\times {10}^{14} \mathrm{Hz}$ is incident on the metal, the cut-off voltage for the photoelectric emission is:

(1) 1.1210 V.

(2) 2.0292 V.

(3) 3.8651 V.

(4) 4.0832 V.

Light of intensity 10^-5 W m^-2 falls on a sodium photo-cell of surface area 2 cm². Assuming that the top 5 layers of sodium absorb the incident energy, The time required for photoelectric emission in the wave-picture of radiation is: (The work function for the metal is given to be about 2 eV.)

(1) 0.2 year

(2) 0.3 year

(3) 0.4 year

(4) 0.5 year