I wasn't there observing the experiment while you and your class
performed it, so I don't really know how it was set up, or what
happened.
But I can tell you this: Light doesn't bend while passing through
any medium. It only bends at the boundary where one medium
meets a different one.
Unit lb mean pound. Which equals to about 0.45 kilograms(kg) /4536 grams,while 1kg equals to about 2.2lb.
Hope it helps!
D. A magnetic field created by the electric current causes the compass needle to move.