Question
Please explain this! Especially the whole part of drift velocity
The current in an electron beam in a cathode-ray tube is measured to be 70 mu A. How many electrons hit the screen in 5.0 s? {e = 1.6 x 10-19 C) 2.2 x 10u electrons. 8.8 x 1013 electrons. 2.2 x 1015 electrons. 8.8 x I018 electrons. A wire carries a steady current of 0.1 A over a period of 20 s. What total charge passes through the wire in this time interval? In a certain material there is a current of 16 A flowing through a surface to the right, and there is an equal amount of positive and negative charge passing through the surface producing the current. How much negative charge passes through the surface? 8 C/s toward the right. 8 C/s toward the left. 16 C/s toward the right. 16 C/s toward the left. 17.2 A Microscopic View: Current and Drift Speed If the current in a wire is tripled, what effect does this have on the electron drift velocity in the wire? It stays the same. It triples. It decreases by a factor of three. It increases by a factor of nine. Wire A and Wire B are each carrying the same current. If the diameter of Wire A is twice that of Wire B, how does the drift velocity vdA in Wire A compare to that in in Wire B?
Explanation / Answer
a)
Q=it =70*10^-6*5 =3.5*10^-4 C
Number of electronsN =I/e =3.5*10^-4/1.6*10^-19
N =2.2*10^15 electrons
b)
Q=It =0.1*20 =2C
3)