Question

In Millikan’s experiment, the potentials which applied to the plates are measured as 750V, 250V, 187.5V and 150V so that the same drop is stationary when its mass is constant. Then the ratio of the charges on the drop is x : y : z : 5. Find x+ y+z is ​

Answer 1

Answer:

given = potentials = 750v , 250v, 187.5v and 150V

to find = ratio  of charges.

solution :-

gravitonal force is unchanged hence balancing force should be same in all case .

force on charge in feild = Eq

E =V/d ............................... V = potential  and d = charge seprations.

vq/ d =mg

vq = mgd

here m,g and d are contant ,

we can write q ∝ 1 /v

we have given ratio =

750 :250:187.5:150..............multiply by 2

1500:500:375:300...................divide by 25

60:20:15:12

q ∝ 1 /v  = 1/60:1/20:1/15:1/12 ..............multiply by  60.

60/60 : 60/20 : 1/18: 1/12

1: 3 :4 : 5..........................charge ratio.

put this value in given equatio...

X +Y +Z = 1 + 3+ 4 = 8

the charges on the drop is 1: 3 :4 : 5.