A Proton Moving with a Velocity Of $4.0 \times 10 ^ { 4 } \mathrm {~m} / \mathrm { s }$

Multiple Choice

A proton moving with a velocity of $4.0 \times 10 ^ { 4 } \mathrm {~m} / \mathrm { s }$ along the $+ y$ -axis enters a magnetic field of $0.20 \mathrm {~T}$ directed towards the $- x$ -axis. What is the magnitude of the magnetic force acting on the proton? $( e$ $= 1.60 \times 10 ^ { - 19 } \mathrm { C }$ )

A) $8.0 \times 10 ^ { - 15 } \mathrm {~N}$
B) $1.3 \times 10 ^ { - 15 } \mathrm {~N}$
C) $2.6 \times 10 ^ { - 15 } \mathrm {~N}$
D) $3.9 \times 10 ^ { - 15 } \mathrm {~N}$
E) $0 \mathrm {~N}$