Exams › JEE Main › Physics

Two like (similarly signed) charges are moved farther apart. What happens to the electric potential energy of the two-charge system?

1. increases
2. decreases
3. remains the same
4. may increase or decrease

Correct answer: may increase or decrease

Solution

U = k q1 q2 / r. As r increases, |U| decreases toward zero in both cases. For like charges (U > 0) the value decreases. For unlike charges (U < 0) the value increases (becomes less negative). Since the question does not fix the sign of the charges, the potential energy may either increase or decrease depending on whether the charges are like or unlike.

Related JEE Main Physics questions

• If an electric field vector E exists in a material whose dielectric constant is K, and ε0 denotes the permittivity of free space, which expression gives the electric displacement vector?
• If a unit positive charge is taken from point A to point B along the same equipotential surface, then what can be said about the potential difference V_A - V_B?
• Two thin metallic spherical shells are placed concentrically with radii R1 and R2, where R1 > R2. If the shells carry charges Q1 and Q2 respectively, what is the electric potential at a point located at distance r such that R2 < r < R1? (Take k = 1/(4πϵ0))
• An alpha particle is made to move through a potential difference of 10⁶ V. What kinetic energy does it gain?
• A parallel-plate capacitor has its entire gap filled with a dielectric whose dielectric constant changes with position x according to K(x) = K0 + λx, where λ is a constant. How is its capacitance C related to the vacuum capacitance C0?
• Two thin circular rings of radius R each are kept on the same axis with their centres separated by a distance d. One ring carries charge +q and the other carries charge −q. What is the potential difference between the centres of the two rings?

⚔️ Practice JEE Main Physics free + battle 1v1 →