Explanation:
(1) The force that exists between charged particles is electrostatic force. It is given by :
[tex]F=k\dfrac{q_1q_2}{r^2}[/tex]
Where
q₁ and q₂ are charges
r is distance between charges
If the charge of a particle doubles, the electric force doubles. So, the correct option is (a) "It doubles".
(2) A charge exerts a negative force on another charge. Negative force denotes the force is attractive. It means that the charges are of opposite sign. So, the correct option is (c) "the charges are of opposite signs".
