JEE Main · 2019 · 10 Apr 2019 · Shift 1 · Modern Physics

WhatsApp Email

In a photoelectric effect experiment the threshold wavelength of the metal is 380 nm. If the wavelength of the incident light is 260 nm, the maximum kinetic energy of the emitted electrons will be: Given E (in eV)

= \frac{1237}{λ ( in nm )}

(A)15.1 eV
(B)1.5 eV✓ Correct
(C)4.5 eV
(D)3.0 eV

Answer: (B)

Solution

The work function is set by the threshold wavelength:

W = \frac{1237}{380} = 3.26 eV

. The incident photon energy is

E = \frac{1237}{260} = 4.76 eV

. Maximum kinetic energy

= E - W = 4.76 - 3.26 \approx 1.5 eV

JEE Main · 2019 · 10 Apr 2019 · Shift 1 · Single correct option

Practise more: all JEE Main PYQs on Modern Physics →

More JEE Main questions on Modern Physics

7.9 MeV α-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.
[ $\frac{1}{4 π ϵ _{0}} = 9 \times 1 0^{9}$ Nm²/C² and electron charge $= 1.6 \times 1 0^{- 19}$ C]
JEE Main 2026View solution →
The minimum frequency of photon required to break a particle of mass 15.348 amu into $4 α$ particles is ______ kHz.
[mass of He nucleus = 4.002 amu, $1$ amu $= 1.66 \times 1 0^{- 27}$ kg, $h = 6.6 \times 1 0^{- 34}$ J.s and $c = 3 \times 1 0^{8}$ m/s]
JEE Main 2026View solution →
The smallest wavelength of Lyman series is 91 nm. The difference between the largest wavelengths of Paschen and Balmer series is nearly $____$ nm.
JEE Main 2026View solution →
Light is incident on a metallic plate having work function $110 \times 1 0^{- 20} J$ . If the produced photoelectrons have zero kinetic energy then the angular frequency of the incident light is ______ $rad / s$ . ( …
JEE Main 2026View solution →
The energy of an electron in an orbit of the Bohr's atom is $- 0.04 E_{0} eV$ where $E_{0}$ is the ground state energy. If L is the angular momentum of the electron in this orbit and h is the Planck's constant, then …
JEE Main 2026View solution →
A particle having electric charge $3 \times 1 0^{- 19} C$ and mass $6 \times 1 0^{- 27} kg$ is accelerated by applying an electric potential of 1.21 V . Wavelength of the matter wave associated with the particle is $α \times 1 0^{- 12} m$ . The va …
JEE Main 2026View solution →