1
JEE Main 2025 (Online) 2nd April Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

A monochromatic light is incident on a metallic plate having work function $\phi$. An electron, emitted normally to the plate from a point A with maximum kinetic energy, enters a constant magnetic field, perpendicular to the initial velocity of electron. The electron passes through a curve and hits back the plate at a point $B$. The distance between $A$ and $B$ is : (Given : The magnitude of charge of an electron is e and mass is $\mathrm{m}, \mathrm{h}$ is Planck's constant and c is velocity of light. Take the magnetic field exists throughout the path of electron)

A
$\sqrt{2 m\left(\frac{h c}{\lambda}-\phi\right)} / \mathrm{eB}$
B
$\sqrt{8 \mathrm{~m}\left(\frac{\mathrm{hc}}{\lambda}-\phi\right)} / \mathrm{eB}$
C
$\sqrt{\mathrm{m}(\mathrm{hc} / \lambda-\phi)} / \mathrm{eB}$
D
$2 \sqrt{\mathrm{~m}(\mathrm{hc} / \lambda-\phi)} / \mathrm{eB}$
2
JEE Main 2025 (Online) 29th January Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

In an experiment with photoelectric effect, the stopping potential,

A

is $\left(\frac{1}{e}\right)$ times the maximum kinetic energy of the emitted photoelectrons

B

increases with increase in the intensity of the incident light

C

decreases with increase in the intensity of the incident light

D

increases with increase in the wavelength of the incident light

3
JEE Main 2025 (Online) 29th January Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

If $\lambda$ and $K$ are de Broglie wavelength and kinetic energy, respectively, of a particle with constant mass. The correct graphical representation for the particle will be :

A
JEE Main 2025 (Online) 29th January Morning Shift Physics - Dual Nature of Radiation Question 20 English Option 1
B
JEE Main 2025 (Online) 29th January Morning Shift Physics - Dual Nature of Radiation Question 20 English Option 2
C
JEE Main 2025 (Online) 29th January Morning Shift Physics - Dual Nature of Radiation Question 20 English Option 3
D
JEE Main 2025 (Online) 29th January Morning Shift Physics - Dual Nature of Radiation Question 20 English Option 4
4
JEE Main 2025 (Online) 29th January Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).

Assertion (A) : Emission of electrons in photoelectric effect can be suppressed by applying a sufficiently negative electron potential to the photoemissive substance.

Reason (R) : A negative electric potential, which stops the emission of electrons from the surface of a photoemissive substance, varies linearly with frequency of incident radiation.

In the light of the above statements, choose the most appropriate answer from the options given below :

A

Both (A) and (R) are true and (R) is the correct explanation of (A).

B

Both (A) and (R) are true but (R) is not the correct explanation of (A).

C

(A) is false but (R) is true

D

(A) is true but (R) is false

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