Answer:
The minimum current in the rod that can cause it to float 2.96 A.
Explanation:
Given;
length of the copper rod, L = 1.43 m
mass of the rod, m = 236 g = 0.236 kg
magnetic field, B = 0.546 T
The magnetic of the rod is given by;
Fm = BIL
The downward force on the rod is given by;
F = mg
For the rod to float, the difference in the two force will be zero;
BIL - mg = 0
BIL = mg
I = mg / BL
I = (0.236 x 9.8) / (0.546 x 1.43)
I = 2.96 A
Therefore, the minimum current in the rod that can cause it to float 2.96 A.