//chapter 1
//example 1.2
//page 18
printf("\n")
printf("given")
l=1*10^-3;E=10;
un=1500*10^-4;up=500*10-4;
Vn=-(un*E)/l;
printf("drift current is %dm/s\n",Vn)
disp("drift current of hole")
Vp=(up*E)/l;
printf("drift current is %dm/s\n",Vp)