It would be 78 becuase the 2 percent of 64 is many of energy lost
C. Increasing the time of the force
This is because
Impulse = FΔt
Answer:
Magnetic field, B = 0.23 T
Explanation:
Given that,
Length of the copper rod, L = 0.49 m
Mass of the copper rod, m = 0.15 kg
Current in rod, I = 13 A (in +ve y direction)
When the rod is placed in magnetic field, the magnetic force is balanced by its weight such that :

So, the magnitude of the minimum magnetic field needed to levitate the rod is 0.23 T.
1). Vector
2). Scalar
3). Magnitude
4). Components
5). Free body diagram