Question

In a crossed field, the magnetic field induction is $2.0T$ and electric field intensity is $20\times {10}^{3}V/m$. At which velocity the electron will travel in a straight line without the effect of electric and magnetic fields?

• A. $\frac{20}{16}\times {10}^{3}m{s}^{-1}$
• B. $10\times {10}^{3}m{s}^{-1}$
• C. $20\times {10}^{3}m{s}^{-1}$
• D. $40\times {10}^{3}m{s}^{-1}$

Answer 1

The correct option is B $10\times {10}^{3}m{s}^{-1}$

$QVB=QE$

$\Rightarrow V=\frac{E}{B}$

$=\frac{20\times {10}^3}{2}=10\times {10}^{3}m/s$