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⚛️ Physics  ·  Moving Charges and Magnetism  ·  NEET & JEE

In a velocity selector, the electric field is 1000 V/m and the magnetic field is 0.5 T. Undeflected particles have speed:

Answer: 2000 m/s.

  • A 250 m/s
  • B 500 m/s
  • C 2000 m/s
  • D 2×10⁶ m/s

Correct answer: C. 2000 m/s

Explanation: v = E/B = 1000/0.5 = 2000 m/s.

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.

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