Understanding how a current balance works is crucial for measuring magnetic flux density in electromagnetism. The current through coils generates a magnetic force that balances with an adjustable weight force, allowing for the calculation of current. To find magnetic flux density, one must measure the current from an ammeter, the length of the wire, and use the formula B = F/I*L, where F is derived from the weight shown on the balance. The discussion highlights the importance of applying the left-hand rule to predict the direction of force and movement in various configurations of current balances. Clarifying the correct lengths and understanding the relationship between current and magnetic fields are essential for solving related problems effectively.