The graph shows how the potential changes along the $x$ axis. In which part is the size of the field greatest, and in which direction does the field point there?

Fig. 1: A graph of potential V in volt against position x in centimetre. The line has five marked points. P is at x = 0 and V = 0 volt. Q is at x = 2 centimetre and V = 10 volt. R is at x = 6 centimetre and V = 10 volt. S is at x = 8 centimetre and V = 4 volt. T is at x = 12 centimetre and V = 0 volt. The line rises steeply from P to Q, runs flat from Q to R, falls steeply from R to S, and falls gently from S to T.