Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
JEE Main2015PhysicsMagnetic Effects of CurrentActual

Two coaxial solenoids of different radii carry current I in the same direction. Let F 1 → be the magnetic force on the inner solenoid due to the outer one and F 2 → be the magnetic force on the outer solenoid due to the inner one. Then:

Options

  1. AF 1 → is radially outwards and F 2 → = 0
  2. BF 1 → = F 2 → = 0
  3. CF 1 → is radially inwards and F 2 → is radially outwards
  4. DF 1 → is radially inwards and F 2 → = 0

Correct answer

B. F 1 → = F 2 → = 0

Step-by-step solution

S 2 is a solenoid with more radius than S 1 , the magnetic field of the solenoid S 2 will be along the axis and constant, so the magnetic force on an element of solenoid S 1 will be, d F → 1 = i l → × B → d F → 1 = i l B j ^ × - i ^ = i B l k ^ Similarly, for just next coil the magnetic field is in same direction, but the current element is in opposite direction, so, d F → 1 = i l B - j ^ × - i ^ = - i B l k ^ . From Symmetry, we can say that the overall force will be ca

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