A discovery not the others
Answer: E = 
Explanation: The formulae for intensity of an electric field of a solid metal sphere relative to a point is given below
r
where
,
, r = 0.1m r = is the position vector of the charge.
it has been stated in the question that the charge is placed at the center thus it has no position vector.

Answer:
The answer is either 5 or I'm learning something different and I just can't read
Explanation:
I hope this helped...
A) Equivalent resistance increases
b) Current through entire circuit decreases
c) Current through the two ( 55 and 75 resistors remains the same), current through 45-resistor is 0.2A