Question

An electron moving with a velocity v = 5.0 × 10^7 m/s i enters a region of space where perpendicular electric and a magnetic fields are present. The electric field is E = 104 V/m j. What magnetic field will allow the electron to go through the region without being deflected?

Answer 1

Answer:

2.08 x 10⁻⁶ T

Explanation:

$v$ = velocity of electron = 5.0 x 10⁷ m/s

q = charge on electron

B = magnetic field = ?

E = electric field = 104 V/m

Magnetic force on the electron is given as

$F_{B} = qvB$

Electric force on the electron is given as

$F_{E} = qE$

For the electron to pass without being deflected, we must have

$F_{B} = F_{E}$

$qvB = qE$

$vB = E$

(5.0 x 10⁷) B = 104

B = 2.08 x 10⁻⁶ T