Which of the following phenomenon will occure when tow atoms of an element with same spein of electron approach each other ?

Which of the following phenomena will occur when two atoms of the elements having same spin of electron approach for bonding ?

Which of the following phenomenon occurs when a chalk stick is dipped in ink?

Which of the following phenomenon occurs when a chalk stick is dipped in ink-

Which one of the following phenomenon occurs when two naked wires of electricity supply line touch other?