Vector A is described as having magnitude -7 and angle 30. Which is an equivalent statement of magnitude and angle of vector A (Note: All angles are measured counterclockwise from the x-axis.) A. magnitude 7; angle 150 degrees
b. magnitude -7; angle -150 degrees
c. magnitude 7; angle 150 degrees
d. magnitude -3.5; angle -30
e. magnitude 7; angle -30

Students in an introductory physics lab are performing an experiment with a parallel-plate capacitor made of two circular aluminum plates, each 11 cm in diameter, separated by 1.0 cm. how much charge can be added to each of the plates before a spark jumps between the two plates? for such flat electrodes, assume that value of 3×106n/c of the field causes a spark.