Question #8e4e9

1 Answer
Apr 15, 2017

#1.02xx10^8" V"#, rounded to two decimal places

Explanation:

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Let the voltage required between the horizontal plates be #=V#
Electric field between the plates#=V/d=V/0.1=10V " Vm"^-1#

Force due to electric field on the proton#=qvecE#
#=1.6 xx 10^-19xx10V#
#=1.6 xx 10^-18V" N"#

Downwards force due to weight of proton#=mg#
#1.67 xx10^-27xx9.81=1.638xx10^-26" N"#

To hold the proton motionless both forces must be balanced. We get
#1.6 xx 10^-18V=1.638xx10^-26#
#=>V=(1.638xx10^-26)/(1.6 xx 10^-18)#
#=>V=1.02xx10^8" V"#, rounded to two decimal places