A student asserts that putting two current-carrying rods next to each other causes them to repel because they carry like charges. Is the student correct?
The student is incorrect.
Assuming this question pertains to putting two current-carrying rods next to each other, where current flows up one of the rods and down the other, the behavior of the rods is actually due to the magnetic field generated in each rod as a result of the current flowing through them. This causes a magnetic force in turn.
When two wires carry a current flowing in the same direction, the wires attract. This is due to the fact that each wire produces a magnetic force toward the other, which is attractive. We can reason this out using the right hand rule.
On the other hand, when the currents are flowing in opposite directions, the wires repel. This can be seen in the below illustration.