= Solution
The <electric field> is force per unit positive stationary test charge, in the limit that the test charge does not disturb the source:
$$
\boxed{\mathbf F_E=q\mathbf E.}
$$
The <magnetic flux density> is defined by the velocity-dependent part of the <Lorentz force>, $\mathbf F_B=q\mathbf v\times\mathbf B$. Equivalently, a straight current element in a uniform field experiences
$$
\boxed{\mathbf F=I\boldsymbol\ell\times\mathbf B,}
$$
which fixes its magnitude and right-hand-rule direction by force measurements with different current orientations.
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