Question
In fair weather the electric field in the airat a particular location immediately above earth's surface is 120N/C directed downward. What is the surface charge density on theground?
Imagine the earth's atmosphere is stripped off and the surfacedensity is uniform over the planet; what then is the charge of thewhole surface of the earth
What is the earth's electric potential
what is the difference in potential between the head and feet of aperson who is 1.75 m tall. In fair weather the electric field in the airat a particular location immediately above earth's surface is 120N/C directed downward. What is the surface charge density on theground?
Imagine the earth's atmosphere is stripped off and the surfacedensity is uniform over the planet; what then is the charge of thewhole surface of the earth
What is the earth's electric potential
what is the difference in potential between the head and feet of aperson who is 1.75 m tall.
Explanation / Answer
The electric field in the air at a particular location aboveearth's surface is E = 120 N/C directed downward. Let the surface charge density on the ground be . Let the charge of the whole surface of the earth be q. The electric field is given by E = (1/4o) * (q/r2)---------------(1) Here,r is the radius of the earth and is equal to 6378.1 km =6378.1 * 103 m From equation (1),we get q = E * 4o* r2 Here,(1/4o) = 9 * 109Nm2/C2 or q = 120 * (1/9 * 109) * (6378.1 *103)2 or q = 542402.1 C Therefore,the charge of the whole surface of the earth is q =542402.1 C. The earth's electric potential is V = (1/4o) * (q/r) or V = 9 * 109 * (542402.1/6378.1 *103) or V = 765.37 * 106 V Therefore,the potential difference between the head and feetof a person is V = E * d Here,d = 1.75 m or V = 120 * 1.75 = 210 V or q = 542402.1 C Therefore,the charge of the whole surface of the earth is q =542402.1 C. The earth's electric potential is V = (1/4o) * (q/r) or V = 9 * 109 * (542402.1/6378.1 *103) or V = 765.37 * 106 V Therefore,the potential difference between the head and feetof a person is V = E * d Here,d = 1.75 m or V = 120 * 1.75 = 210 V