To determine the capacitance when a dielectric slab is inserted, we use the formula for capacitance with a dielectric: \(C' = \frac{\epsilon \cdot A}{d - t + \frac{t}{k}}\), where \(C'\) is the new capacitance, \(\epsilon\) is the permittivity of free space, \(A\) is the area of the plates, \(d\) is the distance between plates, \(t\) is the thickness of the dielectric, and \(k\) is the dielectric constant.
The correct answer is 6.
=(3d+2d)∈0A=5d6∈0A
=56×5μF=6μF
Two charges \( +q \) and \( -q \) are placed at points \( A \) and \( B \) respectively which are at a distance \( 2L \) apart. \( C \) is the midpoint of \( AB \). The work done in moving a charge \( +Q \) along the semicircle CSD (\( W_1 \)) and along the line CBD (\( W_2 \)) are 
Find work done in bringing charge q = 3nC from infinity to point A as shown in the figure : 