All Exams Test series for 1 year @ ₹349 only
Question

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 = $6.63 \times 10^{-34} \text{ J.s}$).

The correct answer is
$1.04 \times 10^{16}$

The problem involves the photoelectric effect. We are given the work function ($\phi$) of a metallic plate, the kinetic energy ($KE$) of the emitted photoelectrons, and Planck's constant ($h$). We need to find the angular frequency ($\omega$) of the incident light.

Photoelectric Effect Principle

According to Einstein's photoelectric equation, the energy of an incident photon ($E_{photon}$) is used to overcome the work function of the metal and provide kinetic energy to the emitted electron:

$E_{photon} = \phi + KE_{max}$

We are given:

  • Work function, $\phi = 110 \times 10^{-20} \text{ J}$
  • Maximum kinetic energy, $KE_{max} = 0 \text{ J}$ (since photoelectrons have zero kinetic energy)
  • Planck's constant, $h = 6.63 \times 10^{-34} \text{ J.s}$

Substituting the values into the equation:

$E_{photon} = (110 \times 10^{-20} \text{ J}) + 0 \text{ J}$

$E_{photon} = 110 \times 10^{-20} \text{ J}$

Photon Energy and Angular Frequency

The energy of a photon can also be expressed in terms of its angular frequency ($\omega$) using Planck's constant:

$E_{photon} = \frac{h\omega}{2\pi}$

Angular Frequency Calculation

Now, we equate the two expressions for photon energy:

$\frac{h\omega}{2\pi} = \phi$

We need to solve for the angular frequency, $\omega$:

$\omega = \frac{2\pi\phi}{h}$

Substitute the given values:

$\omega = \frac{2\pi \times (110 \times 10^{-20} \text{ J})}{6.63 \times 10^{-34} \text{ J.s}}$

Using $\pi \approx 3.14159$:

$\omega = \frac{2 \times 3.14159 \times 110 \times 10^{-20}}{6.63 \times 10^{-34}} \text{ rad/s}$

$\omega = \frac{691.15 \times 10^{-20}}{6.63 \times 10^{-34}} \text{ rad/s}$

$\omega \approx 104.25 \times 10^{(-20 - (-34))} \text{ rad/s}$

$\omega \approx 104.25 \times 10^{14} \text{ rad/s}$

Expressing this in scientific notation with three significant figures:

$\omega \approx 1.04 \times 10^{16} \text{ rad/s}$

Final Answer Derivation

The calculated angular frequency is approximately $1.04 \times 10^{16}$ rad/s. This matches Option D.

Was this answer helpful?

Similar Questions

  1. Assuming in forward bias condition there is a voltage drop of $0.7 \text{ V}$ across a silicon diode, the current through diode $D_1$ in the circuit is ________$\text{mA}$.
    (Assume all diodes in the given circuit are identical)

  2. The ratio of de Broglie wavelength of a deutron with kinetic energy $E$ to that of an alpha particle with kinetic energy $2E$, is $n : 1$. The value of $n$ is ________.
    (Assume mass of proton = mass of neutron) :
  3. The wave numbers of three spectral lines of H atom are considered. Identify the set of spectral lines belonging to Balmer series.
    (R = Rydberg constant)
  4. 7.9 MeV $\alpha$-particle scatters from a target material of atomic number 79. From the given data the estimated diameter of nuclei of the target material is (approximately) _________ m.
    $\left[ \frac{1}{4\pi\epsilon_0} = 9 \times 10^9 \text{ Nm}^2/\text{C}^2 \text{ and electron charge} = 1.6 \times 10^{-19} \text{ C} \right]$
  5. Find the correct combination of A, B, C and D inputs which can cause the LED to glow.

  6. The minimum frequency of photon required to break a particle of mass 15.348 amu into 4 $\alpha$ particles is _________ kHz.
    [mass of He nucleus = 4.002 amu, $1 \text{ amu} = 1.66 \times 10^{-27} \text{ kg}, h = 6.6 \times 10^{-34} \text{ J.s} \text{ and } c = 3 \times 10^8 \text{ m/s}$]
  7. The correct truth table for the given input data of the following logic gate is :

  8. The smallest wavelength of Lyman series is 91 nm. The difference between the largest wavelengths of Paschen and Balmer series is nearly _________ nm.
  9. Two electrons are moving in orbits of two hydrogen like atoms with speeds $3 \times 10^5 \text{ m/s}$ and $2.5 \times 10^5 \text{ m/s}$ respectively. If the radii of these orbits are nearly same then the possible order of energy states are ______ respectively.
  10. Given below are two statements:
    Statement I: For all elements, greater the mass of the nucleus, greater is the binding energy per nucleon.
    Statement II: For all elements, nuclei with less binding energy per nucleon transforms to nuclei with greater binding energy per nucleon.
    In the light of the above statements, choose the correct answer from the options given below

Important Questions from Modern Physics

  1. Assuming in forward bias condition there is a voltage drop of $0.7 \text{ V}$ across a silicon diode, the current through diode $D_1$ in the circuit is ________$\text{mA}$.
    (Assume all diodes in the given circuit are identical)

  2. The ratio of de Broglie wavelength of a deutron with kinetic energy $E$ to that of an alpha particle with kinetic energy $2E$, is $n : 1$. The value of $n$ is ________.
    (Assume mass of proton = mass of neutron) :
  3. The wave numbers of three spectral lines of H atom are considered. Identify the set of spectral lines belonging to Balmer series.
    (R = Rydberg constant)
  4. 7.9 MeV $\alpha$-particle scatters from a target material of atomic number 79. From the given data the estimated diameter of nuclei of the target material is (approximately) _________ m.
    $\left[ \frac{1}{4\pi\epsilon_0} = 9 \times 10^9 \text{ Nm}^2/\text{C}^2 \text{ and electron charge} = 1.6 \times 10^{-19} \text{ C} \right]$
  5. Find the correct combination of A, B, C and D inputs which can cause the LED to glow.

Need Expert Advice?
More Questions from JEE Main

Start Your Preparation with Prepp Mobile App

Download the app from Google Play & App Store
Download the app from Google Play & App Store
Prepp Mobile App