Electric Field

[roy5995]

Originally posted by marshall4
Charge A is +2.5*10^-5C Charge B is -3.7*10^-7C.
A is 25cm away from B. Point C is 10cm away from point B. What is the electric field at C? All points are in a line A--B-C.



Would this work?

Find the electric fields a pont A & B. Then add the two fields ??? Or would you subtract the two fields ???

Use the formula {E} = k\frac{Q}{r^2}


Is the field on point A & B going left or right?

By Reasoning does the electric field at A have to be bigger that B, since A is further away, Or should B be bigger that A , or is there no way of telling, just by looking at the question

[Adrian Baker]

Originally posted by roy5995
Would this work?

Find the electric fields a pont A & B. Then add the two fields ??? Or would you subtract the two fields ???

Use the formula {E} = k\frac{Q}{r^2}


Is the field on point A & B going left or right?

By Reasoning does the electric field at A have to be bigger that B, since A is further away, Or should B be bigger that A , or is there no way of telling, just by looking at the question


In reply to the first part of your question, electric field is a vector quantity. You need to think what is the direction the field due to each charge. Try drawing it.

As one is +ve and the other -ve, both would move a positive charge in the same direction, so you add the values.

You say "Find the electric fields a pont A & B.". Actually you should find the value of the electric fields AT C due to A and at C due to B.