Exams › JEE Main › Physics

Two point charges, +8q at x = 0 and −2q at x = L, are placed on the x-axis. At which position on the x-axis does the resultant electric field due to these charges become zero?

1. L/4
2. 2L
3. 4L
4. 8L

Correct answer: 2L

Solution

The zero-field point is outside the smaller (-2q) charge: 8q/x^2 = 2q/(x-L)^2 -> 2(x-L) = x -> x = 2L.

Related JEE Main Physics questions

• What is the SI unit of the permittivity of free space, ε₀?
• What is the SI unit used for electric flux?
• A constant electric field E is directed along the positive x-axis. If a charge of 0.5 C is displaced by 2 m along a line inclined at 60° to the x-axis, and the work done in this process is 10 J, what is the magnitude of the electric field?
• An electric dipole is located at the origin O along the x-axis. A point P lies 20 cm from O, and the line OP makes an angle π/3 with the x-axis. If the electric field at P is inclined at an angle θ to the x-axis, what is θ?
• A uniformly charged semicircular wire has radius a and linear charge density λ. The magnitude of the electric field at the centre of the semicircle is
• A point Q is located on the perpendicular bisector of an electric dipole whose dipole moment is p. If Q is at a distance r from the dipole and r is much greater than the dipole size, the electric field at Q varies as

⚔️ Practice JEE Main Physics free + battle 1v1 →