a. A thick, perfectly spherical shell made of copper bears a total charge of -24

Question

a. A thick, perfectly spherical shell made of copper bears a total charge of -24 mC. A negatively charged particle at its exact center has one-quarter the total charge of the shell. Find the ratio of the electric flux magnitude outside the shell to that inside its hollow cavity. What would the ratio become if the particle’s charge flipped sign?

b. A uniform field creates an electric flux of 72 J·m/C when passing through a 16 cm by 18 cm rectangular panel that is tilted /3 radians from being perpendicular to the field lines. What is the magnitude of the electric field intensity? If the panel is rotating on its axis of tilt with an angular frequency of 2 radians per second, find an expression for the rate of change of the flux with respect to time.

Explanation / Answer

a] electric flux inside = q/e0

electric flux outside = [4q-q]/e0 =3q/e0

ratio of ouside flux to inside flux = 3:1

if sign is changed, electric flux outside = [4q+q]/e0 =5q/e0

  ratio of ouside flux to inside flux = 5:1

b] flux = E*A*cos theta

72 = E*0.16*0.18* cos pi/3

E = 72/[0.16*0.18* cos pi/3]

= 5000 N/C

RATE of flux change = d[E*A*cos theta]/dt

= E*A* sin theta * dtheta/dt

= 5000*0.16*0.18* [sin (2pi/3)] * 2pi

= 784 W.m/C

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

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