1
JEE Main 2025 (Online) 24th January Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

In photoelectric effect, the stopping potential $\left(\mathrm{V}_0\right) \mathrm{v} / \mathrm{s}$ frequency $(v)$ curve is plotted.

( h is the Planck's constant and $\phi_0$ is work function of metal )

(A) $\mathrm{V}_0 \mathrm{v} / \mathrm{s} v$ is linear.

(B) The slope of $\mathrm{V}_0 \mathrm{v} / \mathrm{s} v$ curve $=\frac{\phi_0}{\mathrm{~h}}$

(C) h constant is related to the slope of $\mathrm{V}_0 \mathrm{v} / \mathrm{s} v$ line.

(D) The value of electric charge of electron is not required to determine h using the $\mathrm{V}_0 \mathrm{v} / \mathrm{s} v$ curve.

(E) The work function can be estimated without knowing the value of $h$.

Choose the correct answer from the options given below :

A
(A), (C) and (E) only
B
(C) and (D) only
C
(A), (B) and (C) only
D
(D) and (E) only
2
JEE Main 2025 (Online) 24th January Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

An electron of mass ' m ' with an initial velocity $\overrightarrow{\mathrm{v}}=\mathrm{v}_0 \hat{i}\left(\mathrm{v}_0>0\right)$ enters an electric field $\overrightarrow{\mathrm{E}}=-\mathrm{E}_{\mathrm{o}} \hat{\mathrm{k}}$. If the initial de Broglie wavelength is $\lambda_0$, the value after time t would be

A
$\frac{\lambda_o}{\sqrt{1-\frac{\mathrm{e}^2 \mathrm{E}_{\mathrm{o}}^2 \mathrm{t}^2}{\mathrm{~m}^2 \mathrm{v}_{\mathrm{o}}^2}}}$
B
$\lambda_0$
C
$\frac{\lambda_o}{\sqrt{1+\frac{\mathrm{e}^2 \mathrm{E}_{\mathrm{o}}^2 \mathrm{t}^2}{\mathrm{~m}^2 v_o^2}}}$
D
$\lambda_{\mathrm{o}} \sqrt{1+\frac{\mathrm{e}^2 \mathrm{E}_{\mathrm{o}}^2 \mathrm{t}^2}{\mathrm{~m}^2 \mathrm{v}_{\mathrm{o}}^2}}$
3
JEE Main 2025 (Online) 23rd January Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

In photoelectric effect an em-wave is incident on a metal surface and electrons are ejected from the surface. If the work function of the metal is 2.14 eV and stopping potential is 2 V , what is the wavelength of the em-wave? (Given $\mathrm{hc}=1242 \mathrm{eVnm}$ where h is the Planck's constant and c is the speed of light in vaccum.)

A
400 nm
B
600 nm
C
300 nm
D
200 nm
4
JEE Main 2025 (Online) 23rd January Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

A sub-atomic particle of mass $10^{-30} \mathrm{~kg}$ is moving with a velocity $2.21 \times 10^6 \mathrm{~m} / \mathrm{s}$. Under the matter wave consideration, the particle will behave closely like $\qquad$ $\left(\mathrm{h}=6.63 \times 10^{-34} \mathrm{~J} . \mathrm{s}\right)$

A
X-rays
B
Infra-red radiation
C
Gamma rays
D
Visible radiation
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