Question

The velocity of certain ions that pass undeflected through crossed electric field $E = 7.7 k\, V/m$ and magnetic field $B = 0.14\, T$ is

• A. $18\,km/s$
• B. $77\,km/s$
• C. $55\,km/s$
• D. $1078\,km/s$

Answer 1

Answer: (C)

$55\,km/s$

Answer 2

As velocity $v=\frac{E}{B}=\frac{7.7\times10^{3}}{0.14}=55\,km/s$