Two tiny metal spheres are fixed to the ends of a non-conducting string of length

\ell

.Equal charges,+q,are placed on the metal spheres.Randall says that the force on the string has magnitude

\frac { 1 } { 2 \pi \varepsilon _ { 0 } } \frac { q ^ { 2 } } { \ell ^ { 2 } }

.Tilden says that the tension in the string has magnitude

\frac { 1 } { 2 \pi \varepsilon _ { 0 } } \frac { q ^ { 2 } } { \ell ^ { 2 } }

.Which one,if either,is correct?
A)Randall,because both charges exert forces on the string,but the tension is

\frac { 1 } { 4 \pi \varepsilon _ { 0 } } \frac { q ^ { 2 } } { \ell ^ { 2 } }

.
B)Tilden,because both charges exert forces on the string,but the net force is

\frac { 1 } { 4 \pi \varepsilon _ { 0 } } \frac { q ^ { 2 } } { \ell ^ { 2 } }

.
C)Both are correct,because both charges exert forces on the string.
D)Neither is correct,because both the tension and the force have magnitude

\frac { 1 } { 4 \pi \varepsilon _ { 0 } } \frac { q ^ { 2 } } { \ell ^ { 2 } }

.
E)Neither is correct,because the tension is

\frac { 1 } { 4 \pi \varepsilon _ { 0 } } \frac { q ^ { 2 } } { \ell ^ { 2 } }

,but the net force is 0.

Identical Point Charges Q Are Placed at Each of the Four

Multiple Choice