1. A -20nC charge is located at the origin. What is the strength of the electric
ID: 2138225 • Letter: 1
Question
1. A -20nC charge is located at the origin.
What is the strength of the electric field at the position (x,y)=(?5.0cm,?5.0cm)?
What is the strength of the electric field at the position (x,y)=(?5.0cm,5.0cm)?
2. A 30 nC charged particle and a 50 nC charged particle are near each other. There are no other charges nearby. The electric force on the 30 nC particle is 3.30Ý10?2N . The 50 nC particle is then moved very far away.
Afterward, what is the magnitude of the electric field at its original position?
3. Objects A and B are both positively charged. Both have a mass of 200g , but A has twice the charge of B. When A and B are placed with 5.0cm between their centers, B experiences an electric force of 0.35N .
How large is the force on A?
What is the charge qA?
What is the charge qB?
Explanation / Answer
1) q = -20 nC
r = sqrt(0.05^2+0.05^2) = sqrt(2)*0.05m
at(-5,-5) r = sqrt(2)*0.05m, E = k*q/r^2 = 36000 N/C
at(-5,+5) r = sqrt(2)*0.05m, E = k*q/r^2 = 36000 N/C
2)
F = 3.3*10^-2N
q1 = 30 nC
q2 = 50 nC
E = F/q2 = 3.3*10^-2/50*10^-9 = 0.066*10^7 = 6.6*10^5 N/c
3)
force on A is same as B, 0.35N
m1 = m2 = 0.2 kg, r = 0.05 m
qa = 2*qb
F = k*qa*qb/r^2
0.35 = k*2*qb^2/r^2
qb = sqrt( 0.35*0.05^2/(2*9*10^9) )
qb = 0.022*10^-5 C
qb = 2.2*10^-7 C
qa = 2*qb = 4.4*10^-7 C
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.