1.

In the uniform electic field of E=1 xx 10^(4), NC^(-1), an electron is accelerated from rest. The velocity of the electron when it has travelled a distance of 2 xx 10^(-2)m is nearly (e/m" of electron " approx 1.8 xx 10^(-11)Ckg^(-1))

Answer»

`8.5 xx 10^(6) ms^(-1)`
`1.6 xx 10^(6) ms^(-1)`
`0.85 xx 10^(6) ms^(-1)`
`0.425 xx 10^(6) ms^(-1)`

Solution :By work-energy THEOREM,
Work done by electric FIELD =Change in KE of electron
or `q Ex =1/2 mv^(2)`
`or v=sqrt((2qEx)/(m))`
`=sqrt(2 xx 1.8 xx 10^(11) xx 1 xx 10^(4) xx 2 xx 10^(-2))`
`=8.5 xx 10^(6)ms^(-1)`.


Discussion

No Comment Found

Related InterviewSolutions