CBSE Class 12 · 2023 · Magnetic Effects of CurrentMultiple Choice

Beams of electrons and protons move parallel to each other in the same direction. They

(A)Attract each other✓ Correct
(B)Repel each other
(C)Neither attract nor repel
(D)Force of attraction or repulsion depends upon speed of beams

Answer: (A)

Solution

The beams carry opposite charges, so the electrostatic force between them is attractive. An electron beam moving in the

+ x

direction is a conventional current in

- x

, while the proton beam is a current in

+ x

; these anti-parallel currents repel. At ordinary (non-relativistic) speeds the electric force dominates the magnetic one, so the net effect is attraction.

CBSE Class 12 Board · 2023 · Single correct option

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