1. || 2 X 10m electrons flow through a cross section of an iron wire of 4 mm diameter in 10 s. What is the electron drift speed? 19. II A 15-cm-long nichrome wire is connected across the termi- nals of a 1.5 V battery. a. What is the electric field inside the wire? b. What is the current density inside the wire? c. If the current in the wire is 2.0 A, what is the wire's diameter?27. | What is the resistance of a. A 2.0-m-long gold wire that is 0.20 mm in diameter? b. A 10-cm-long piece of carbon with a 1.0 mm X 1.0 mm square cross section?33. | Pencil "lead" is actually carbon. What is the current if a 9.0 V potential difference is applied between the ends of a 0.70-mm- diameter, 6.0-cm-long lead from a mechanical pencil?40. II The electron beam inside an old television picture tube is 0.40 mm in diameter and carries a current of 50 uA. This electron beam impinges on the inside of the picture tube screen. a. How many electrons strike the screen each second? b. What is the current density in the electron beam? c. The electrons move with a velocity of 4.0 X 10' m/s. What electric field strength is needed to accelerate electrons from rest to this velocity in a distance of 5.0 mm? d. Each electron transfers its kinetic energy to the picture tube screen upon impact. What is the power delivered to the screen by the electron beam?47. I The starter motor of a car engine draws a current of 150 A from the battery. The copper wire to the motor is 5.0 mm in diameter and 1.2 m long. The starter motor runs for 0.80 s until the car engine starts. a. How much charge passes through the starter motor? b. How far does an electron travel along the wire while the starter motor is on