Zaymiey

⚛️ Physics  ·  Moving Charges and Magnetism  ·  NEET & JEE

An electron moving at 2 &times; 10<sup>6</sup> m/s enters a field of 0.5 T perpendicularly. The force on it is (e = 1.6 &times; 10<sup>-19</sup> C):

Answer: 1.6 10 -13 N.

  • A 3.2 &times; 10<sup>-13</sup> N
  • B 1.6 &times; 10<sup>-13</sup> N
  • C 0.8 &times; 10<sup>-13</sup> N
  • D 1.6 &times; 10<sup>-19</sup> N

Correct answer: B. 1.6 &times; 10<sup>-13</sup> N

Explanation: F = qvB = 1.6 &times; 10<sup>-19</sup> &times; 2 &times; 10<sup>6</sup> &times; 0.5 = 1.6 &times; 10<sup>-13</sup> N.

Magnetic Field Lines Around a Straight WireIfield forms concentric circles around the wire (right-hand rule)

The magnetic field around a long straight current-carrying wire forms concentric circles, with direction given by the right-hand rule (point thumb along I, fingers curl in the direction of B).

Concept context

Magnetic force on moving charges and currents, the Biot-Savart law, Ampere's law, and the cyclotron - how electric currents create and respond to magnetic fields.

Read the full Moving Charges and Magnetism notes →