Q26. A bar magnet has total length 2l = 20 units and the field point P is at a distance d = 10 units from the centre of the magnet. If the relative uncertainty of length measurement is 1% , then uncertainty of the magnetic field at point P is : (1) 4% (2) 15% (3) 5% (4) 10%
What This Question Tests
This question combines the formula for the magnetic field on the axial line of a bar magnet with the concept of error propagation, specifically relative uncertainty calculations.
Concepts Tested
Formulas Used
B_axial = (μ₀/4π) * (2Md / (d^2 - l^2)^2)
ΔB/B = |∂B/∂l| * Δl / B
📚 NCERT Sections This Tests
4.4 — A Horizontal Overhead Power Line Carries A Current Of 90 A In East To
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4.4 A horizontal overhead power line carries a current of 90 A in east to west direction. What is the magnitude and direction of the magnetic field due to the current 1.5 m below the line?
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4.8 A closely wound solenoid 80 cm long has 5 layers of windings of 400 turns each. The diameter of the solenoid is 1.8 cm. If the current carried is 8.0 A, estimate the magnitude of B inside the solenoid near its centre.
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4.6 A 3.0 cm wire carrying a current of 10 A is placed inside a solenoid perpendicular to its axis. The magnetic field inside the solenoid is given to be 0.27 T. What is the magnetic force on the wire?
📋 Question Details
- Chapter
- Magnetic Effects of Current
- Topic
- Magnetic field of a bar magnet (axial line)
- Year
- 2025
- Shift
- 28 Jan Shift 2
- Q Number
- Q26
- Type
- MCQ
- NCERT Ref
- Class 12 Physics Ch 5: Magnetism and Matter
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