Question

20. A coil with 10 turns of area 0.05m is place in a magnetic field of strength 0.4 T. The coil is then rotated in such a way that the cosine of the angle between a perpendicular to plane of the coil and the field changes uniformly from 0.0 to 1.0 in 10 seconds. The EMF induced in the coil during this period is: a. 20.0 V b. 2.0 V c. 0.2 V d. 0.02 V 21. Which of the following is a possible equation for the electric field of an electromagnetic wave with average intensity 0.00132W/m traveling in the +z direction with a magnetic field along the x axis? a. E = (2 V/m) sin [(9.8 x 106/mz+ (2.9 x10 Hz)t] i b. E = (1 V/m) sin [(9.8 x 106/m) - (2.9 x10'S Hz)t) c. E = (1 V/m) sin [(9.8 x 106 /m) - (2.9 x101S Hz)t) i d. E = (2 V/m) sin [(9.8 x 106 / m z+ (2.9 x 1015 Hz)t] 22. Two parallel wires are separated by Imm, Each is 2m long and carries a current of 3A in the same direction as the other. The forces the two wires exert on each other: a. Has magnitude 0.0036 N and repels the wires from each other. b. Has magnitude 0.0036 N and attract the wires to each other. c. Has magnitude 0.00015 N and repels the wires from each other. d. Has magnitude 0.00015 N and attract the wires to each other.

Answer 1

20.

o= BA cose

B4 Cose, Acos - cos ; tę - ti dt

1.0 - 0.0 = 10 x 0.4 x 0.05 x = 10 dt

e = 0.02

21.

22.

F = Mo 21112. 47 d

F = 10-74 10-72 x 3 x 3 0.001 - X2

F = 3.6 x 10-3 N

and attract the wires to each other.

F=0,0036