Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
NEET2019PhysicsMagnetic Effects of CurrentActual

A particle of mass m and charge q moves with a constant velocity v along the positive x -direction. It enters a region containing a uniform magnetic field B directed along the negative z direction, extending from x=a to x=b . The minimum value of v required so that the particle can just enter the region x>b is

Options

  1. Aq b B / m
  2. Bq(b-a) B / m
  3. Cq a B / m
  4. Dq(b+a) B / 2 m

Correct answer

B. q(b-a) B / m

Step-by-step solution

aligned r= & m v q B =b-a & ( for just entering) v & = q(b-a) B m aligned

Practice Magnetic Effects of Current on Quantrex Academy →

More from Magnetic Effects of Current

The magnitude of the magnetic induction (B) at a point on the axis at a large distance 'r' from the centre of a circular coil of 'n' turns and area 'A' carrying current ' i ' is gi 2026For a circular coil of radius a , at what distance x along its axis the magnetic field is exactly 1 27 of its value at the center? 2026A circular coil having 'n' turns, each of radius 'r' carries a current 'I'. The magnetic field at a distance x = 8 r from its centre along axis of the coil is ( ₀ = permeability of 2026The ratio of cyclotron frequency f to the radius of the path of a charged particle R is q^2 B^2 2 m^2 x . Then the value of x is ( v is velocity of charged particle) 2026In a cyclotron, for the same values of B and R, what is the ratio of the maximum kinetic energies of particles and deuteron? Mass of deuteron =2m_p , charge on deuteron =+e 2026The magnitude of the magnetic field at point O (centre of the arc) with radius R, in the following case is ( ₀ = permeability of free space, I = current and R is the radius of circ 2026Two wires of same material A and B, having lengths l and 2l 3 carry the currents I and 3I 4 respectively. Both the wires (A and B) are bent into a circles (of single turn). If B_A 2026An electron is projected with uniform velocity along the axis of a current carrying long solenoid. Which of the following is true? a. The electron will be accelerated along the axi 2026 Full Magnetic Effects of Current list All NEET PYQs