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Saturday, 31 October

JEE Main 2023 · PhysicsNumerical answerNumerical valueMediumCalculation

JEE Main 10 April 2023, Shift 1, Physics Q58

Question 58 of 90 in this shift, Physics question 28 of 30, Section B.

A 1 m long metal rod XYXY completes the circuit as shown in figure. The plane of the circuit is perpendicular to the magnetic field of flux density 0.15 T. If the resistance of the circuit is 5 Ω5\,\Omega, the force needed to move the rod in direction, as indicated, with a constant speed of 4 m/s will be ____________ 10−3 N10^{-3}\,N.

The figure, in words

Rectangular circuit with a 5 ohm resistor on the left side; a vertical metal rod XY (X at top, Y at bottom) slides on the top and bottom rails, velocity v drawn as an arrow to the right; magnetic field into the page shown as crosses throughout.

Official answer

18

NTA final key.

Chapter
Electromagnetic Induction
Topic
Faraday's Law
Idea tested
Linear Motional EMF

Same idea in other shifts

Asked 7× in all
  1. 8 Apr 2023, Shift 2 · Q48An emf of 0.08 V is induced in a metal rod of length 10 cm held normal to a uniform magnetic field of 0.4 T, when moves with a velocity of:EasySingle correct
  2. 11 Apr 2023, Shift 2 · Q58A metallic cube of side 15 cm15\ \mathrm{cm} moving along y-axis at a uniform velocity of 2 ms−12\ \mathrm{ms^{-1}}. In a region of uniform…MediumNumerical valueHas a figure
  3. 27 Jun 2022, Shift 2 · Q59A metallic rod of length 20 cm is placed in North-South direction and is moved at a constant speed of 20 m/s towards East. The horizontal…MediumNumerical value
  4. 4 Aug 2021, Shift 1 · Q10A metal rod of 10 cm length is moving with a velocity 5 m/s at the centre of a current carrying circular coil of radius 4 cm and 2A…MediumSingle correct
  5. 4 Aug 2021, Shift 1 · Q14The magnetic field in any region is given by B⃗=B0(2+xa)k^\vec{B}=B_0\left(2+\frac{x}{a}\right)\hat{k}. A square loop of edge length ‘l’ is placed…MediumSingle correct
  6. 26 Feb 2021, Shift 2 · Q7An aeroplane, with its wings spread 10 m, is flying at a speed of 180 km/h in a horizontal direction. The total intensity of earth’s field…MediumSingle correct

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. This question needs a figure we do not reproduce; it is described in words above. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.