JEE Main · Physics · Moving Charges and Magnetism
Ratio of Axial to Central Magnetic Field
JEE Main asked Ratio of Axial to Central Magnetic Field 5 times in 5 of the 108 shifts Lumi analysed, in 2021, 2022, 2023 and 2025. It belongs to Biot-Savart Law, in Moving Charges and Magnetism (Physics). The longest wait between two years asking it was 2 years. In 2022 it came in more than one shift of the same year.
Updated 2026-10-24
- Times asked
- 5
- in 5 shifts
- Years
- 4 of 8
- First asked
- 2021
- last in 2025
- Pattern
- Comes in cycles
- across the analysed shifts
Questions on this idea a shift, by year
2017–2026. Asked in 2021, 2022, 2023 and 2025. Years differ in how many shifts Lumi analysed, so each year is scaled to one shift of 25 Physics questions.
Raw count: 2017: 0 in 1 shift · 2020: 0 in 12 shifts · 2021: 1 in 24 shifts · 2022: 2 in 24 shifts · 2023: 1 in 12 shifts · 2024: 0 in 18 shifts · 2025: 1 in 8 shifts · 2026: 0 in 9 shifts.
Shift by shift
Each square is one analysed shift, in date order. Open a filled one for that paper.
How JEE Main framed it
Single correct is the usual form. Skill tested: calculation.
- Axial to central field ratio
- Ratio of coil fields centre vs axis
Difficulty
1 of the 5 questions had a numerical answer.
Every question
All 5 questions
From the official JEE Main shift papers, newest first. Open one for the full question, the options and the official answer.
- 2 Apr 2025, Shift 1 · Q38Let be the magnitude of magnetic field at center of a circular coil of radius R carrying current I. Let be the magnitude of…EasySingle correct
- 8 Apr 2023, Shift 2 · Q59The ratio of magnetic field at the centre of a current carrying coil of radius to the magnetic field at distance from the centre…MediumNumerical value
- 24 Jun 2022, Shift 1 · Q49The magnetic field at the centre of a circular coil of radius r, due to current I flowing through it, is B. The magnetic field at a point…EasySingle correct
- 28 Jul 2022, Shift 2 · Q13The magnetic field at the center of current carrying circular loop is . The magnetic field at a distance of times…EasySingle correct
- 26 Aug 2021, Shift 1 · Q11The fractional change in the magnetic field intensity at a distance ‘r’ from centre on the axis of current carrying coil of radius ‘a’ to…MediumSingle correct
Shifts: 26 Aug 2021, Shift 1, 24 Jun 2022, Shift 1, 28 Jul 2022, Shift 2, 8 Apr 2023, Shift 2, 2 Apr 2025, Shift 1.
Same topic
Other ideas in Biot-Savart Law
Biot-Savart Law has 11 ideas JEE Main has asked; 9 of them came up in more than one question.
- Field at center of circular arc8× · 2025
- Superposition of magnetic fields5× · 2026
- Field at Center of Regular Polygon5× · 2025
- Field of an N-Turn Flat Coil4× · 2026
- Infinite and semi-infinite wires4× · 2024
- Dimensions of Permeability3× · 2025
- Field on axis of circular loop2× · 2023
- Field at Center of Spiral Coil2× · 2022
- Vector form of Biot-Savart Lawonce · 2024
- Field of a Hairpin Looponce · 2021