Question

A velocity selector consists of electric and magnetic fields described by the expressions e with arrow = e k and b with arrow = b ĵ, with b = 22.0 mt. find the value of e such that a 850-ev electron moving in the negative x direction is undeflected.

Answer 1

380.38 kV/m

Step-by-step explanation:

We are given that

`Electric field=E`

Magnetic field,B=22 mT=
`22* 10^(-3) T`

`1mT=10^(-3) T`

K.E=850e V=
`850* 1.6* 10^(-19) J`

Charge on electron,q=
`1.6* 10^(-19) C`

Mass of electron,m=
`9.1* 10^(-31) kg`

Speed of electron,v=
`\sqrt{(2K.E)/(m)`

`v=\sqrt{(2* 850* 1.6* 10^(-19))/(9.1* 10^(-31))}`

`v=17.29* 10^6 m/s`

`E=vB=17.29* 10^6* 22* 10^(-3)=380.38* 10^3 V/m=380.38KV/m`

1 kV=
`10^3 V`