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Moving Charges and Magnetism — Physics STD 12 Science — Question

Bihar BoardEnglish MediumSTD 12 SciencePhysicsMoving Charges and Magnetism1 Mark
Question
Two statements are given-one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.
  1. Both A and R are true and R is the correct explanation of A.
  2. Both A and R are true but R is NOT the correct explanation of A.
  3. A is true but R is false.
  4. A is false and R is also false.
Assertion (A): An electron and proton enters a magnetic field with equal velocities, then, the force experienced by proton will be more than electron.
Reason (R): The mass of proton is 1999 times more than the mass of electron.
✓

Answer

  1. A is false and R is also false.

Explanation:

The force experienced by a charge particle in a magnetic field is given by,

$\vec{\text{F}}=\text{q}(\vec{\text{v}}\times\vec{\text{B}})$

which is independent of mass. As q, v and Bare same for both the electron and proton, hence both will experience same force.

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