Question

In the given figure, the electron enters into the magnetic field. It deflects in which direction ?



(1)+ve x-direction
(2)–ve x-direction
(3)+ve y-direction
(4)–ve y-direction

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Answer 1

question : In the given figure, the electron enters into the magnetic field. it deflects in which direction ?

1. +ve x - direction
2. -ve x - direction
3. +ve y - direction
4. -ve y - direction

solution : this question can be solved by two methods (1) analytical method (2) Flemming's right hand palm method.

Flemming's right hand palm method : Thumb shows the direction of charge, rest four fingers show the direction of magnetic field and palm shows the direction of magnetic force applied on the charge.

here we get direction of deflection of charge in negative y - direction, if you arrange your right hand.

Therefore option (4) is correct choice.

analytical method : using formula,

F = q(v × B)

here direction of v along +ve x direction. let v = i

direction of magnetic field -ve z direction, B = -k

and charge = -e [ charge of electron is negative]

so, F = -e [i × -k ]

= -e [j ]

= e(-j)

here direction of force is -j i.e., negative y - direction.

so electron deflects -ve y - direction.

Therefore option (4) is correct choice.

Answer 2

Negative y- direction (4)