Question

The table below shows four pairs of atoms and the electric charge of each atom. The atoms in each pair are located the same distance from each other.

Pair Atom A Atom B
W +4 +7
X -8 -3
Y +7 +5
Z -9 -4

Which pair of atoms is experiencing the strongest electric force?
A.
Pair X
B.
Pair Y
C.
Pair W
D.
Pair Z

Answer 1

Coulomb's law: F = k|q1·q2|/r^2. With r the same for all pairs, compare |q1·q2|:

- W: |4·7| = 28
- X: |−8·−3| = 24
- Y: |7·5| = 35
- Z: |−9·−4| = 36

Largest is 36 (pair Z). Answer: D.