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An electron is projected horizontally wi...

An electron is projected horizontally with a kinetic energy of 10 keV. A magnetic field of strength `1.0X10^(-7)` T exists in the vertically upward direction.
(a)will the electron deflect towards right or towards left of its motion?
(b) calculate the sideways deflection of the electron in travelling through 1m. make appropriate approximations.

Text Solution

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`KE = 10Kev = 1.6 xx 10 ^(-16) J` ,
` B = 1xx 10 ^(-7) T ` ,
` (a) The eletron will be deflected towards left .
`(b) (1/2 } mv ^2) =KE `rArr V = sqrt (KE xx 2) /(m)` ,
` F= qVB ` rArr accln = qVB/m `
applying s = ut + (1) /(2) at^2`
= (1)/(2) (16 xx 10 ^(-10) xx 1 xx 10^(-7) xx 1 ) (/91 xx 10^(-31))`
By solving we get ,
a = 0.0148 = n1.5 xx 10 ^(-2) cm. `
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