Gravitational force of attraction "f" exists between two-point masses a and b when a fixed distance separates them. after mass a is doubled and mass b is quartered, the gravitational attraction between the two masses

8F

Explanation:

Given

Gravitation attraction is F between A and B

if and is the mass of A and B respectively then

F is given by

where r=distance between them

if is doubled and is quadrupled then Force can be given by

thus force becomes 8 times of initial value

current and voltage can both be different in different parts of a circuit so it matters where you place the ammeter and voltmete