[phy] electrostatics (一條AL MC)

Only statement (1) is correct.

When the +ve charged rod is brought near, electrons are attracted, from Y, towards the side of X close to the rod. Hence, X becomes -ve charged and Y becomes +ve charged. But because both X and Y are earthed, electrons flow from earth towards Y and neutralize the +ve charge. At steady state, X is -ve charged and Y is neutral.

Because electrons at X are attracted by the +ve charged rod, these lectrons cannot flow to earth.

Statements (3) and (4) are both wrong. It is because both spheres are earthed, they are kept at earth (i.e. zero) potential.