The induced electromotive force (emf) $\varepsilon$ generated between the center (axle) and the rim of a rotating conductor (like a wheel or rod) in a uniform magnetic field perpendicular to the plane of rotation is given by the formula : $\varepsilon = \frac{1}{2} B \omega R^2$ Where: $B$ is the magnetic field strength ($0.1 \text{ T}$). $\omega$ is the angular velocity ($10 \text{ rad/s}$).

• $R$ is the radius or length of the conductor ($0.5 \text{ m}$).

Calculation: $\varepsilon = \frac{1}{2} \times 0.1 \times 10 \times (0.5)^2$ $\varepsilon = 0.5 \times 1 \times 0.25$ $\varepsilon = 0.125 \text{ V}$

Note: Even if the wheel has multiple spokes, they are connected in parallel between the center and the rim, so the net emf remains the same as that of a single spoke .