Quizbank/Electricity and Magnetism (calculus based)/QBCh5

QB153086031104

QB:Ch 5:V1

QB153086031104

1)

Three small charged objects are placed as shown, where $b=2a$, and $a=2\times 10^{-7}{\text{m}}$.what angle does the force on $q_{2}$ make above the $-x$ axis if $q_{1}=2e$, $q_{2}=-7e$, and $q_{3}=5e$?

a) 4.357E+01 degrees

b) 4.793E+01 degrees

c) 5.272E+01 degrees

d) 5.799E+01 degrees

e) 6.379E+01 degrees

2)

A ring is uniformly charged with a net charge of 7 nC. The radius of the ring is R=1.7 m, with its center at the origin and oriented normal to the z axis as shown. What is the magnitude of the electric field at a distance z=1.2 m (on axis) away from the loop's center?

a) 6.925E+09 N/C²

b) 7.617E+09 N/C²

c) 8.379E+09 N/C²

d) 9.217E+09 N/C²

e) 1.014E+10 N/C²

3)  $E(z)=\int _{0}^{R}f(r',z)dr'$
is an integral that calculates the magnitude of the electric field at a distance $z$ fromthe center of a thin circular disk as measured along a line normal to the plane of the disk. The disk's radius is $R=8.1{\text{ m}}$ and the surface charge density is $\sigma =3{\text{ nC/m}}^{3}$. Evaluate $f(r',z)$ at $r'=4.2{\text{ m}}$.

a) 5.134E-01 V/m²

b) 5.648E-01 V/m²

c) 6.212E-01 V/m²

d) 6.834E-01 V/m²

e) 7.517E-01 V/m²