Final answer:
The wire cd will rise to an equilibrium height h due to the magnetic force exerted on it by the current in wire ab.
Step-by-step explanation:
The wire cd will rise to an equilibrium height h due to the magnetic force exerted on it by the current in wire ab. The magnetic force on wire cd is given by the equation F = iLB, where i is the current in wire ab, L is the length of wire cd, and B is the magnetic field strength. The force exerted by the weight of wire cd is given by the equation F = mg, where m is the mass per unit length of wire cd and g is the acceleration due to gravity.
At equilibrium, the magnetic force is equal to the weight force, so we can set the two equations equal to each other:
iLB = mg
From this equation, we can solve for the equilibrium height h:
h = L - (mg)/(iB)