Electric Field Strength and Potential

[elemis]

Page 10 part (b) (ii) <click on the link

Now, the question states :

Use Fig. 4.2 to state and explain the distance x at which the rate of change of
potential with distance is maximum

Now electric field strength = negative potential gradient

So in effect they're asking for the point at which electric field strength is maximum, correct ?

Now isn't maximum electric field strength at 1.4 cm because electric field strength has the greatest value at that point ?

The marking scheme provided disagrees and gives an answer of 11.4 cm...

But at 11.4 cm the electric field strength is highly negative...

 

[gneill]

Rate of change can be positive or negative. It's the magnitude of the rate of change that counts, not it's sign.