JEE Main 2024 · PhysicsMultiple choiceSingle correctMediumApplication

JEE Main 31 January 2024, Shift 1, Physics Q42

Question 42 of 90 in this shift, Physics question 12 of 30, Section A.

A rigid wire consists of a semicircular portion of radius

R

and two straight sections. The wire is partially immerged in a perpendicular magnetic field

B=B_0\hat{j}

as shown in figure. The magnetic force on the wire if it has a current

i

is:

The figure, in words

Rigid wire: semicircular arch of radius R at the top with two parallel straight sections going down (dashed lines at the bottom); current arrows up on the left leg and down on the right leg. Region of uniform magnetic field drawn as dots (field out of the page) over the whole wire; axes x (right), y (up) with z out of the page at the origin shown.

(1) $2iBR\hat{j}$
(2) $-2iBR\hat{j}$ Official answer
(3) $iBR\hat{j}$
(4) $-iBR\hat{j}$

Official answer

Option 2

NTA final key.

Chapter: Moving Charges and Magnetism
Topic: No close match in our taxonomy
Idea tested: No close match in our taxonomy