Which of the following is a chemical change? A. Water vapor in the air turns to liquid water in the form of rain
B. The oxygen in the air forms ozone in presence of UV rays
C. Dust and soot particles being suspended in the air
D. Sulphur dioxide being released in the air

Electric field of the earth. the earth has a net electric charge that causes a field at points near its surface equal to 150 n> c and directed in toward the center of the earth. (a) what magnitude and sign of charge would a 60-kg human have to acquire to overcome his or her weight by the force exerted by the earth’s electric field? (b) what would be the force of repulsion between two people each with the charge calculated in part (a) and separated by a distance of 100 m? is use of the earth’s electric field a feasible means of flight? why or why not?