Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
JEE Main201912 Apr 2019Morning ShiftPhysicsMagnetic Effects of CurrentActual

A thin ring of 10 c m radius carries a uniformly distributed charge. The ring rotates at a constant angular speed of 40 π r a d s - 1 about its axis, perpendicular to its plane. Is the magnetic field its centre is 3.8 × 10 - 9 T , then the charge carried by the ring is close to μ 0 = 4 π × 10 - 7 N / A 2 .

Options

  1. A4 × 10 - 5 C
  2. B3 × 10 - 5 C
  3. C2 × 10 - 6 C
  4. D7 × 10 - 6 C

Correct answer

B. 3 × 10 - 5 C

Step-by-step solution

i = q t = q 2 π / ω = q ω 2 π B = μ 0 i 2 R = μ 0 q ω 4 π R 4 π × 10 - 7 × q × 40 π 4 π × ( 0.1 ) = 3.8 × 10 - 9 q × 400 π = 3.8 × 10 - 2 q = 3 × 10 - 5 C

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