1) Earth's atmosphere is constantly bombarded by cosmic ray protons that originate somewhere in space. If the protons all passed through the atmosphere, each square meter of Earth's surface would intercept protons at the average rate of 1200 protons per second. What would be the electric current in amperes intercepted by a 49 x 107 km2 area on the planet?
2) A charged nonconducting rod, with a length of 2.13 m and a cross-sectional area of 3.20 cm2, lies along the positive side of an x axis with one end at the origin. The volume charge density ? is charge per unit volume in coulombs per cubic meter. How many excess electrons are on the rod if ? is
(a) uniform, with a value of -2.67 µC/m3, and
(b) nonuniform, with a value given by ? = bx2, where b = -2.68 µC/m5?
3) If a cat repeatedly rubs against your cotton slacks on a dry day, the charge transfer between the cat hair and the cotton can leave you with an excess charge of -2.00 ?C.
(a) How many electrons are transferred between you and the cat? You will gradually discharge via the floor, but if instead of waiting, you immediately reach toward a faucet, a painful spark can suddenly appear as your fingers near the faucet.
(b) In that spark, do electrons flow from you to the faucet (type 1) or vice versa (type 0)?
(c) Just before the spark appears, do you induce positive (type 1) or negative (type 0) charge in the faucet?
(d)If, instead, the cat reaches a paw toward the faucet, which way do electrons flow in the resulting spark (from faucet to the cat - type 1, or vice versa - type 0)?