a charge of -1.00nC and a mass os 1.00x10^-12kg has a velocity of 5.00x10^3m/s.

Question

a charge of -1.00nC and a mass os 1.00x10^-12kg has a velocity of 5.00x10^3m/s. It enters a region of uniform electric and magnetic fields. the magnetic field B=-1.5T k.

a)calculate the magnitude and direction of teh electric field if the charge is to pass through teh field undeflected. (answe:+7500 N/C i)

b)if the electric field is turned off, what is the radius of the path of charge (answer: 3.33m)

c) sketch a path of the charge with only the magnetic field present

d)in this case, how long is the charge in the magnetic field? (answer:2.09ms)

Explanation / Answer

Known:
q=-1x10^-9 C
m= 1x10^-12 kg
v = 5x10^3 m/s
B= -1.5 T k

a) Electric Field?

E= F/q

F= qv x B (cross product)
F= qvBsin() (it will follow a circular path so = 90)
F=qvB
F=( -1x10^-9 C *5x10^3 m/s * -1.5Tk)
F=7.5x10^-6N

Substitute for E=F/q

E=(7.5x10^-6N)/-1x10^-9 C
E= 7500 N/C i (By RHR)

b) Radius?

We use F=qvB.

Since centripital force is:

F=ma=m(v^2/r)
We get:

m(v^2/r) = qvB

r=(mv)/(qB)
r=(1x10^-12 kg * 5x10^3 m/s)/(-1x10^-9 C * -1.5T)

r= 3.33 m

d) Time in magnetic field?

time : (distance)/(velocity)

Period : T (one full circle)

T = 2r/v = (2*3.33m)/(5x10^3m/s) = 4.185 ms

Since it did not travel a full circle divide by 2:

4.185m/s / 2

t = 2.09 ms

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.