Two positive charge of 12cand 8c are 10cm apart each other. The work done in bringing them 4cm closer is

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To calculate the work done in bringing two charges closer, we need to consider the electric potential energy associated with the charges.

The formula for electric potential energy is given by:

PE = k * (q1 * q2) / r

Where PE is the electric potential energy, k is the electrostatic constant (8.99 x 10^9 N*m^2/C^2), q1 and q2 are the magnitudes of the charges in Coulombs, and r is the distance between the charges in meters.

Given that the charges are 12 C and 8 C, and they are initially 10 cm apart, we can convert the distance to meters by dividing by 100:

r_initial = 10 cm / 100 = 0.1 m

Since we are bringing the charges 4 cm closer, we can calculate the final distance as:

r_final = r_initial - 4 cm / 100 = 0.1 m - 0.04 m = 0.06 m

Now we can calculate the work done using the formula:

Work_done = PE_initial - PE_final

PE_initial = k * (q1 * q2) / r_initial
PE_final = k * (q1 * q2) / r_final

Plugging in the values, we get:

PE_initial = (8.99 x 10^9 N*m^2/C^2) * (12 C * 8 C) / 0.1 m
PE_initial = 8.99 x 10^9 * 96 / 0.1 J

PE_final = (8.99 x 10^9 N*m^2/C^2) * (12 C * 8 C) / 0.06 m
PE_final = 8.99 x 10^9 * 96 / 0.06 J

Now we can calculate the work done:

Work_done = PE_initial - PE_final

Substituting the values and performing the calculation will give you the answer in Joules.