Eletric field and charges Questions

In a region, the potential is represented by V(x, y, z) = 6x − 8xy − 8y + 6yz, where V is in volts and x, y, z are in metres. The electric force experienced by a charge of 2 coulomb situated at point (1, 1, 1) is

Two identical tennis balls each having mass ‘m’ and charge ‘q’ are suspended from a fixed point by threads of length ‘L’. What is the equilibrium separation when each thread makes a small angle ‘θ’ with the vertical?

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An infinitely long straight wire carries uniform linear charge. It produces electric field 3.6 × 10⁵ N/C at 5 cm. Find linear charge density.