A 25 cm long bar magnet (AB) is moved with a speed of 8m/s in a magnetic field of 0.02 Tesla as shown in figure. The emf generated is:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 0.04 V
A conductor of length \( l \) moving with speed \( v \) at right angles to a magnetic field \( B \) has a motional emf \( \varepsilon = Blv \). In the figure the rod AB moves along the rails, perpendicular to the field (shown into the page), so the full formula applies.
\( l = 25\,\mathrm{cm} = 0.25\,\mathrm{m} \)
\( \varepsilon = Blv = 0.02\,\mathrm{T}\times0.25\,\mathrm{m}\times8\,\mathrm{m\,s^{-1}} = 0.04\,\mathrm{V} \)