Three equal point charges, each with charge 1.30 μC , are placed at the vertices of an equilateral triangle whose sides are of length 0.400 m .
1. What is the electric potential energy U of the system? (Take as zero the potential energy of the three charges when they are infinitely far apart.) Use ϵ0 = 8.85 x 10^−12 C^2N*m^2 for the permittivity of free space.

Explanation:

Given

Three Point charges with equal  charge

Side length of triangle

Potential energy between two charges is given by

where and are the charges and d is the distance between them

For three charges

Substitute the values

hi there!

out of the two, (b) precision would be more reasonable.   however, both a and b could be pretty reasonable.

-awesomerepublic   : )

the answer is the first electromagnet (a). this is because it has more coils around the ferromagnetic material. increasing the number of coils increases the surface area in which the metal interacts with the current in the coil. this enables more atoms in the metal to become aligned hence becoming more magnetized.