PHYSICS 232
Midterm 1, February 19 , 1996, 10:00am-11:00am
Instructor: P. Q. Hung

25 points for each problem. READ the problems carefully. SHOW YOUR WORK. DO NOT JUST write the answers down.

) A wire carries a steady current of 2.0 A. (a) How much charge flows through a cross-sectional area of the wire in 5.0 min? (b) How many electrons flow through the cross-sectional area in this time?

a)

b) electrons

) A certain dielectric with a dielectric constant = 24 can withstand an electric field of V/m. Suppose we want to use this dielectric to construct a 0.1- F ( F) capacitor that can withstand a potential difference of 2000 V. (a) What is the minimum plate separation? (b) What must the area of the plates be?

a)

b)