- #1

- 4

- 2

## Homework Statement

The electric field on the axis of a uniformly charged ring has magnitude 360 kN/C at a point 6.2 cm from the ring center. The magnitude 19 cm from the center is 150 kN/C ; in both cases the field points away from the ring.

## Homework Equations

1. Find the ring's radius.

2. Find the ring's charge.

## The Attempt at a Solution

E=kxQ/(x

^{2}+ a

^{2})

^{3/2}

360000 = kQ(.062)/(.062

^{2}+a

^{2})

^{3/2}

150000 = kQ(.19)/(.19

^{2}+a

^{2})

^{3/2}

360/150 = (.062/.19) * ((.062

^{2}+a

^{2})/(.19

^{2}+a

^{2}))

^{3/2}

(360/150 * .19/.062)

^{2/3}= (.062

^{2}+a

^{2})/(.19

^{2}+a

^{2})

(360/150 * .19/.062)

^{2/3}* (.19

^{2}+a

^{2})= .062

^{2}+a

^{2}

(360/150 * .19/.062)

^{2/3}* (.19

^{2}) - .062

^{2}= a

^{2}- (360/150 * .19/.062)

^{2/3}* a

^{2})

-0.00247871714 = -2.7819469745 a^2

a = sqrt(0.00247871714/2.7819469) = .030 m = 3.0 cm

Which turned out to be incorrect, and with an incorrect radius, I've got nothing to go off of for charge

Last edited: