A small glass bead has been charged to 8.0 nC. What is the magnitude of the electric field 2.0 cm from the center of the bead? (k = 1/40 = 8.99 109 N m2/C2)
A) 3.6 10-6 N/C B) 1.4 10-3 N/C C) 1.8 105 N/C D) 3.6 103 N/C
Question 2
Two circular coils of diameter 30.0 cm are parallel to each other and have their centers along the same line L but separated by 22.0 cm. When an experimenter views the coils along L, the coil closer to her carries a clockwise current of 2.50 A.
Find the magnitude and sense (clockwise or counterclockwise) of the current needed in the other coil so that the net magnetic field on L midway between the two coils will have a magnitude of 4.10 T and point away from the experimenter who is viewing the coils along L. (0 = 4 10-7 T m/A)