Question

Two point charges are separated by 25.0 cm(see (Figure 1) ). Assume that q1 = -6.00 nC and q2= -14.5 nC .

A. Find the net electric field these charges produce at point A.

Express your answer in newtons per coulomb to three significant figures.

B. Find the net electric field these charges produce at point B.

Express your answer in newtons per coulomb to three significant figures.

C. What would be the magnitude of the electric force this combination of charges would produce on a proton at A?

Express your answer in newtons to three significant figures.

D. What would be the direction of the electric force this combination of charges would produce on a proton at A? (Left or Right)

Answer 1

A)
q1 and q2 are the same polarity so their fields subtract between them
E at A is then k*14.5e-9/0.1² - k*6.0e-9/0.15²
= ((8.99*10^9*14.5e-9)/0.1²) - ((8.99*10^9*6.0e-9)/0.15²)
= 10638.16 N/C pointing left A)
B)
At point B the fields from the charges add since they are in the same direction, to the left
k*6.0e-9/0.1² + k*14.5e-9/0.35²
=((8.99*10^9*6.0e-9)/0.1²) + ((8.99*10^9*14.5e-9)/0.35²)
= 6458.12 N/C B)
C-D)
10638.16*1.6e-19 = 1.702e-15 N directed towards right