Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
JEE Main2018PhysicsMagnetic Effects of CurrentActual

A Helmholtz coil has a pair of loops, each with N turns and radius R . They are placed coaxially at distance R and the same current I flows through the loops in the same direction. The magnitude of the magnetic field at P , midway between the centres A and C , is given by [Refer to figure given below]:

Options

  1. A8 N μ 0 I 5 1 / 2 R
  2. B4 N μ 0 I 5 3 / 2 R
  3. C4 N μ 0 I 5 1 / 2 R
  4. D8 N μ 0 I 5 3 / 2 R

Correct answer

D. 8 N μ 0 I 5 3 / 2 R

Step-by-step solution

Magnetic field at point P, due to both coils, B p = 2 μ 0 N I R 2 2 R 2 + R 2 4 3 / 2 = μ 0 N I R 2 5 3 / 2 8 R 3 =   8 N μ 0 I 5 3 / 2 R .

Practice Magnetic Effects of Current on Quantrex Academy →

More from Magnetic Effects of Current

A hollow, right circular cone of base radius R and height h , with its tip at the origin is rotating about the Z -axis with an angular velocity , as shown in the figure. The cone c 2026In a vacuum chamber, a particle of charge 1 C and mass 1 mg is projected with a velocity ( i + 2 j ) ms ⁻¹ from the XZ plane at time t = 0 in an electric field of 1 i Vm ⁻¹ . At t 2026A current carrying circular loop of radius 2 cm with unit normal n = k + i 2 is placed in a magnetic field, B = B₀(3 i +2 k ) . If B₀ = 4 10⁻³ T and current I=100 2 A, the torque e 2026A 5 mg particle carrying a charge of 5 10⁻⁶ C is moving with velocity of (3 i +2 k ) 10⁻² m/s in a region having magnetic field B = 0.1 k Wb/m ^2 . It moves a distance of meter alo 2026A current of 30 A each flows in opposite directions in two conducting wires, placed parallel to each other at a distance of 8 cm. The magnetic field at the mid point between the tw 2026A small cube of side 1 mm is placed at the centre of a circular loop of radius 10 cm carrying a current of 2 A. The magnetic energy stored inside the cube is 10⁻¹⁴ J. The value of 2026The charged particle moving in a uniform magnetic field of (3 i + 2 j ) T has an acceleration (4 i - x 2 j ) m/s ^2 . The value of x is __________. 2026A circular coil of radius 2 cm and 125 turns carries a current of 1 A. The coil is placed in a uniform magnetic field of magnitude 0.4 T. The axis of the coil makes an angle of 30° 2026 Full Magnetic Effects of Current list All JEE Main PYQs