Question

A jet plane having a wing-span of 25 m is travelling horizontally towards east with a speed of 3600 km/hour. If the Earth?s magnetic field at the location is $4 \times 10^{-4} \, T$ and the angle of dip is $30^{\circ}$, then, the potential difference between the ends of the wing is

• A. 4 V
• B. 5 V
• C. 2 V
• D. 2.5 V

Answer 1

Answer: (B)

5 V

Answer 2

Motional emf: $e = B_v \,vl$
$B_v = B \, \sin \, \theta = 4 \times 10^{-4} \times \sin \, 30 = 2 \times 10^{-4 } \,T$
$v = 3600$ km/hour = $3600 \times \frac{5}{18} 1000 \,ms^{-1}$
$e = 2 \times 10^{-4} \times 1000 \times 25 = 5 \,V$