Question

in a region a uniform magnetic field acts in horizontal plane towards north if cosmic particles (80% proton) falling vertically downwards then they are deflected towards
a) North b) South c)East d) West​

Answer 1

answer:

option (c) toward east

Answer 2

Given info : in a region a uniform magnetic field acts in horizontal plane towards north if cosmic particles (80% proton) falling vertically downwards.

To find : they are deflected towards ...

solution : using Fleming's left hand rule, you can easily find the deflection of cosmic particles. according to this rule, thumb represents thrust or deflection of charge, fore finger represents the direction of magnetic field, and the central finger represents the direction of the propagation of the charge.

here, magnetic field acts in horizontal plane towards north, cosmic particles are falling vertically downwards so the deflection of cosmic particles will be east direction.

analytical method : magnetic fields acts northwards so magnetic field = B j

cosmic particles moves downwards so propagation of charge ( direction of proton is direction of current) = - l k

now using magnetic force, F = i (l × B) = i (-l k × B j) = Bil  i^ (positive x direction which means east )

therefore the deflection of cosmic particles will be east.