Question

A jet plane is travelling west at the speed of $1600\, km \,h^{-1}$. The voltage difference developed between the ends of the wing having a span of $20\, m$, if the earth’s magnetic field at the location has a magnitude of $5 \times 10^{-4}\, T$ and the dip angle is $30^{\circ}$ is

• A. $4.1\,V$
• B. $2.2\,V$
• C. $3.2\, V$
• D. $3.8\, V$

Answer 1

Answer: (B)

Here, $v=1600\,km\,h^{-1}$
$=1600\times\frac{5}{18}=444\,m\,s^{-1}$
$l=20\,m$,
$B =5\times10^{-4}\,T$ and $ \delta=30^{\circ}$
As $\varepsilon=Blv=Vlv$
(where $V$ is the vertical component of earths field)
$=\left(B\,sin\,\delta\right)lv$ $\left(\because V=Bsin\delta\right)$
$=5\times10^{-4}\,sin\,30^{\circ}\times20\times444$
$=2.2\,V$