Two charges q1 and q2 are seperated by distance r in free space
what happens to the froce
1.If the charges are doubled
2.distance is halfed
3.if the medium of dielectric constant K is introduced

Question

Two charges q1 and q2 are seperated by distance r in free space
what happens to the froce 
1.If the charges are doubled
2.distance is halfed
3.if the medium of dielectric constant K is introduced

anonymous · Answer

in 1 and 2, force becomes 4  times. in 3, the force reduces by k times. do you know coulomb's law of electrostatics. your question can be solved by direct formula application only

ujjwal · Answer

Electrostatic force is directly proportional to product of charges
And inversely proportional to square of distance between them..
that will help you in 1st and 2nd part of your question
For the third part: the introduction of dielectric increases the permittivity by k times and decreases the electrostatic force by k times..

stormfire1 · Answer

As Soham051994 said, if you know the formula these become quite easy:$$F=k\frac{q_1q_2}{r^2}$$