Q. A house has a floor area of 113 m2 and an outside wall that has an area of 26 m2. The earth's magnetic field here has a horizontal component of 3.0 multiplied by 10-5 T that points due north and a vertical component of 4.9 multiplied by 10-5 T that points straight down, toward the earth.
Q. Protons move in a circle of radius 4.40 cm in a 0.510 T magnetic field. What value of electric field could make their paths straight?