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Equipotential surfaces are shown in the diagram at right. Explain all answers. I

ID: 1456649 • Letter: E

Question

Equipotential surfaces are shown in the diagram at right. Explain all answers. If the proton were placed at point P, how would it move How much net work would be required to move the proton form point P to point R How much energy would the proton acquire or lose if allowed to move form P to the shell it would travel to spontaneously The value of capacitor C in the diagram is muF. The potential difference across C is 10V. Find the equivalent capacitance between points C and D. Find the charge on the top 2 muF capacitor In the Circuit the battery has a voltage of 10V. Find the equivalent resistance of the

Explanation / Answer

Here ,

a) as the electric field points in the direction of decreasing the potential .

hence, the direction of electric field is radially outwards

as the proton is positively charged

the direction of force on the proton is radially outwards

the proton will move radially outwards.

b)

net work required to move from P to R = (VR - VP) * e

net work required to move from P to R = (100 - 80) * 1.602 *10^-19

net work required to move from P to R = 3.204 *10^-18 J

c)

energy from point P to shell

energy from point P = VP * e

energy from point P = 80 * 1.602 *10^-19 J

energy from point P = 1.282 *10^-17 J

hence , 1.282 *10^-17 J is needed for the proton to move from P spontaneously.

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a) for 2 uF and 2 uF and C in series

1/C1 = 1/2 + 1/2 + 1/8

C1 = 0.275 uF

for C1 and 3 uF in parallel

Cp = C1 + 3

Cp = 3.275 uF

the capacitance between C and D is 3.275 uF

b) for the top 2 uF

charge on the 2 uF capacitor = V * C1

charge on the 2 uF capacitor = 10 V* 0.275 uF

charge on the 2 uF capacitor = 2.75 uC