Question

What should be the magnitude and direction of electric field?

• A. $7N{c}^{-1}$, Vertically up $\perp$ to velocity
• B. $7N{c}^{-1}$, horizontally and $\perp$ to velocity
• C. $14N{c}^{-1}$, horizontally parallel to velocity
• D. none of these

Answer 1

Answer: (B)

$7N{c}^{-1}$, horizontally and $\perp$ to velocity

$\overrightarrow{v}\times \overrightarrow{B}=E$

If angle between B and v is $\frac{\pi }{2}$

$v$ = $\frac{E}{B}$

or $vB$ = $14\left(0.5\right)$ = $7N{C}^{-1}$

Thus magnitude of electric field is 7 and direction is horizontal, perpendicular to velocity