Two small conducting spheres of equal radius | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(B) According to Coulomb's Law,the force between two point charges is given by $F = k \frac{Q_1 Q_2}{R^2}$.Initially,the charges are $Q_1 = +10\,\mu C

Vedclass · Accepted Answer

$-8:1$

Vedclass · Answer

(B) According to Coulomb's Law,the force between two point charges is given by $F = k \frac{Q_1 Q_2}{R^2}$.Initially,the charges are $Q_1 = +10\,\mu C$ and $Q_2 = -20\,\mu C$. The force is $F_1 = k \frac{(10)(-20)}{R^2} = -200 \frac{k}{R^2}$.When the spheres are brought into contact,the total charge is redistributed equally because the spheres have equal radii. The new charge on each sphere is $Q' = \frac{Q_1 + Q_2}{2} = \frac{10 - 20}{2} = -5\,\mu C$.After separation to the same distance $R$,the new force is $F_2 = k \frac{(-5)(-5)}{R^2} = 25 \frac{k}{R^2}$.The ratio of the forces is $\frac{F_1}{F_2} = \frac{-200 \frac{k}{R^2}}{25 \frac{k}{R^2}} = \frac{-200}{25} = -8$.Thus,the ratio $F_1 : F_2$ is $-8:1$.

Similar Questions

$A$ charge $Q$ is divided into two parts $q$ and $Q - q$. If the Coulomb repulsion between them when they are separated by a distance $r$ is to be maximum,the ratio of $\frac{Q}{q}$ should be:

An infinite number of charges,each of charge $1 \,\mu C$,are placed on the $x$-axis at coordinates $x = 1, 2, 4, 8, ... \infty$. If a charge of $1 \, C$ is kept at the origin,what is the net force acting on the $1 \, C$ charge in Newtons?

Four charges are arranged at the corners of a square $ABCD$,as shown in the adjoining figure. The force on the charge kept at the centre $O$ is

Three point charges $+q$,$+2q$,and $+4q$ are placed along a straight line such that the charge $+2q$ is equidistant from the other two charges. The ratio of the net electrostatic force on charges $+q$ and $+4q$ is

Two similar tiny balls of mass $m$,each carrying charge $q$,are hung from silk threads of length $l$ as shown in the figure. These are separated by a distance $x$ and the angle $2\theta$ is small. Then,for equilibrium:

Vedclass Test Series

Exam Paper Generator

Online Exam Module