Question

Your friend sets up a uniform electric field (in units of N/C): E(x,y)=−3100i−2500j What do you predict you will measure to be the voltage difference for the displacement going from position (-30,47) to position (-42,-25) with distances measured in centimeters?

I've tried this using two different methods. The first one I used was deltaV=Ed which gave me 3982.46 V. The second was the dot product of <-3100,2500> and <-.12,-.72> which gave me -1428 V. Neither answer was correct. What am I doing wrong?

Answer 1