JEE Main 2021 · PhysicsMultiple choiceSingle correctEasyCalculation

JEE Main 25 July 2021, Shift 2, Physics Q14

Question 14 of 90 in this shift, Physics question 14 of 30, Section A.

Two ions having same mass have charges in the ratio 1 : 2. They are projected normally in a uniform magnetic field with their speeds in the ratio 2 : 3. The ratio of the radii of their circular trajectories is :

(1)4 : 3Official answer
(2)2 : 3
(3)3 : 1
(4)1 : 4

Official answer

Option 1

NTA final key.

Chapter: Moving Charges and Magnetism
Topic: Lorentz Force
Idea tested: Circular Motion in Uniform B-Field

Same idea in other shifts

Asked 7× in all

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9 Jan 2020, Shift 2 · Q14An electron gun is placed inside a long solenoid of radius $R$ on its axis. The solenoid has $n$ turns/length and carries a current $I$ .…MediumSingle correctHas a figure

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.