A Beam of Electrons Is Accelerated Through a Potential Difference $1.0 \mathrm { kV }$

Multiple Choice

A beam of electrons is accelerated through a potential difference of $1.0 \mathrm { kV }$ before entering a velocity selector. If the magnetic field of the velocity selector has a magnitude of $0.010 \mathrm {~T}$ , what magnitude of the electric field is required if the electrons are not to be deflected as they pass through the velocity selector? $\left( \left( e = 1.60 \times 10 ^ { - 19 } \mathrm { C } , m _ { \mathrm { e } } \right. \right.$ lectron $\left. = 9.11 \times 10 ^ { - 31 } \mathrm {~kg} \right)$

A) $5.9 \times 10 ^ { 3 } \mathrm {~V} / \mathrm { m }$
B) $1.9 \times 10 ^ { 5 } \mathrm {~V} / \mathrm { m }$
C) $1.1 \times 10 ^ { 5 } \mathrm {~V} / \mathrm { m }$
D) $6.0 \times 10 ^ { 5 } \mathrm {~V} / \mathrm { m }$
E) $7.2 \times 10^6 \mathrm {~V} / \mathrm { m }$