Here are the corrections for questions 20-30 Pg 599 (courtesy of Caitlyn)
20.a) out of page, over top
b)counterclockwise
c)into page, over top
d) clockwise
e) into page, over top
21. a) out (circle)
b) out (left) in (right)
c) left to right
d) in (X)
e) out (right), in (left)
f) right to left
22. answers in textbook are correct
23. a) out left, in right
b) in left, out right
24. and 25. answers in textbook are correct
26. a) field down, force left
b) north top, field right
27. a) field up, current out
b) north top, current out
28. a) north top, field down
b) north bottom, field up
29. answers in textbook are correct