Step 1:

Diameter of the ring is .

Charge on each ring is .

Diastance between the rings is m.

Radius of the ring is m.

Electric field strength for a ring with radius and distance from the center of the ring is .

Find the elcetric field strengthat mid point.

Charge on mid point is resultant of both left and right rings on that point.

Elcetric field strength Contribution of left ring:

Diastance from the left ring t the mid point is m.

Substitute corresponding values in the formula.

.

Since moid point is considered , the magntude of the right ring contribution is also same as the left ring and is in oppsit direction.

.

(ii)

Find the field strength at the center of the left ring.

Contribution of left ring:

Diastance from the left ring to that point itself is zero.

Contribution of right ring:

Diastance from the right ring to center of the left ring is m.

Substitute corresponding values in the formula.

.

Therefore field strength at the center of the left ring is .