JIPMER2017PhysicsElectrostatics
A charged particle ' q ' is shot with speed v towards another fixed charged particle Q . It approaches Q upto a closest distance r and then returns. If q were given a speed 2 v , the closest distance of approach would be
Options
- Ar
- B2 r
- Cr / 2
- Dr / 4
Correct answer
D. r / 4
Step-by-step solution
At closest distance r its whole KE is converted into PE 1 2 m v^2= 1 4 ₀ Q q r r= 1 4 ₀ Q q m v^2 In next case, r^ = 1 4 ₀ Q q m(2 v)^2 r^ = 1 4 ( 1 4 ₀ Q q m v^2 ) r^ =r / 4