1
JEE Main 2025 (Online) 28th January Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
JEE Main 2025 (Online) 28th January Evening Shift Physics - Magnetic Effect of Current Question 20 English

An infinite wire has a circular bend of radius a, and carrying a current I as shown in the figure. The magnitude of magnetic field at the origin O of the arc is given by:

A
$\frac{\mu_0}{2 \pi} \frac{\mathrm{I}}{\mathrm{a}}\left[\frac{\pi}{2}+2\right]$
B
$\frac{\mu_0}{4 \pi} \frac{\mathrm{I}}{\mathrm{a}}\left[\frac{3 \pi}{2}+1\right]$
C
$\frac{\mu_0}{4 \pi} \frac{\mathrm{I}}{\mathrm{a}}\left[\frac{\pi}{2}+1\right]$
D
$\frac{\mu_0}{4 \pi} \frac{\mathrm{I}}{\mathrm{a}}\left[\frac{3 \pi}{2}+2\right]$
2
JEE Main 2025 (Online) 28th January Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

The frequency of revolution of the electron in Bohr's orbit varies with n, the principal quantum number as:

A

$ \frac{1}{n^4} $

B

$ \frac{1}{n^2} $

C

$ \frac{1}{n^3} $

D

$ \frac{1}{n} $

3
JEE Main 2025 (Online) 28th January Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

Earth has mass 8 times and radius 2 times that of a planet. If the escape velocity from the earth is 11.2 km/s, the escape velocity in km/s from the planet will be:

A

8.4

B

11.2

C

5.6

D

2.8

4
JEE Main 2025 (Online) 28th January Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

Which of the following phenomena cannot be explained by wave theory of light?

A

Refraction of light

B

Reflection of light

C

Diffraction of light

D

Compton effect

JEE Main Papers
2023
2021
EXAM MAP