The magnetic force on a current-carrying conductor is given by the formula \( F = B \cdot I \cdot L \cdot \sin(\theta) \), where \( B = 0.4 \, \text{T} \), \( I = 2 \, \text{A} \), \( L = 3 \, \text{m} \), and \( \theta = 30^\circ \).
\[
F = 0.4 \cdot 2 \cdot 3 \cdot \sin(30^\circ) = 2.4 \, \text{N}.
\]