Magnetic Effect of Current – JEE Main 2026 Quiz

Q1. Ratio of magnetic field at centre of a circular coil of radius r to the magnetic field at distance r on its axis is √x : 1. Find x.

Q2. A current of 5 A flows in a square loop of side 1 m. Magnetic field at the centre is X√2 × 10⁻⁷ T. Find X.

Q3. A rod of length 60 cm rotates with angular velocity 20 rad s⁻¹ about its perpendicular bisector in a uniform magnetic field of 0.5 T (parallel to axis). Potential difference across the rod (in V) is:

Q4. For a circular coil, if x : R = 3 : 4, then the ratio B₂ / B₁ is:

Q5. A straight wire of length 4 cm carrying current 8 A is perpendicular to a uniform magnetic field of 0.15 T. Magnetic force on the wire (in mN) is:

Q6. A single turn loop in shape of a right angled triangle (5 cm, 12 cm, 13 cm) carries current 2 A in a magnetic field of 0.75 T. Force on 5 cm side is x/130 N. Find x.

Q7. Magnetic field inside a solenoid with 200 turns, current 0.29 A is 2.9×10⁻⁴ T. Length of solenoid is ____ π cm.

Q8. A square loop of side 1/√2 m carries current 5 A. Magnetic field at centre is p × 10⁻⁶ T. Find p.

Q9. Torque on a rectangular loop in a uniform magnetic field of 2×10⁻³ T is:

Q10. An optical medium has relative permeability 10/π and relative permittivity 1/0.0885. Velocity of light in vacuum is greater by ____ times.