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## Homework Statement

Two parallel metal plates 5.0 cm apart have a potential difference between them of 75 V. The electric force on a positive charge of 3.2*10^-19 C at a point midway between the plates is approximately

a. 1.6*10^-18 N

b. 2.4*10^-17 -

c. 4.8*10^-18

d. 4.8*10^-16

e. 9.6*10^-17

## Homework Equations

V = E*d = (F/q)*d

## The Attempt at a Solution

F = (V*q)/d = (75 V)*(3.2*10-19 C)/(0.025 m) = 9.6*10^-16 N?

But this does not match any of the choices . . .except for being close to E.

Is my arithmetic wrong or is the question in need of editing?

## Homework Statement

The electric potential in a region of space is given by V(x,y,z)=10 (V/m)x +20 V/m(y) + 30(V/m)z. The z-component of the electric field in this region is

a. (-30 V/m)*k vector

b. (-10 V/m)*i vector

c. (20 V/m)*j vector

d. (-20 V/m)*j vector

e. (30 V/m)*k vector

## Homework Equations

See below.

## The Attempt at a Solution

Is the answer e. (30 V/m)*k vector since V/m = N/C (both units for electric field)?

## Homework Statement

When 5.0 C of charge moves at constant speed along a path between two points differing in potential by 12 V, the amount of work done by the electric field is

a.2.4 J

b. 0.42 J

c. 5.0 J

d. 12 J

e. 60 J

## Homework Equations

U = q*V ?? (correct formula?)

## The Attempt at a Solution

U = 5.0 C*12V = 60 J?

Thanks.

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