Figure 2 shows two magnets, supported on a yoke, placed on an electronic balance - AQA - A-Level Physics - Question 2 - 2017 - Paper 2

The left magnet should be labeled 'N' (North) and the right magnet 'S' (South). This configuration indicates the direction of the magnetic field from North to South.

The tesla (T) is the SI unit of magnetic flux density. It is defined as the amount of magnetic flux (measured in webers) passing through a unit area (measured in square meters) perpendicular to the direction of the magnetic field. One tesla is equivalent to one weber per square meter.

Using the formula for magnetic force: $B = \frac{F}{I \cdot l}$, where ( F = mg ) with ( m = 0.620 g = 0.000620 kg ), ( g = 9.81 ,m/s^2 ), ( I = 3.43 , A ), and ( l = 0.0500 , m ):

1. Calculate the force: $F = 0.000620 \, kg \cdot 9.81 \, m/s^2 = 0.0060782 \, N$

2. Substitute into the formula for B: $B = \frac{0.0060782 \, N}{3.43 \, A \cdot 0.0500 \, m} = 0.0350 \, T \approx 0.036 \, T$