An unknown wire in a circuit has a circular cross-section with diameter 3.9 mm. It carries a current of 1.3 mA. Required:
a. What is the current density, in milliamperes per square centimeter, in this wire?
b. If you assume the drift velocity in this wire is 1 Ã 10^-2 cm/s, what is the density of charge carries per cubic centimeter?
c. If the conductivity in this wire is 5.5 à 10^6 Ω^-1 m-1, what is the average time between collisions, in nanoseconds?

Question 7 [2 marks] in the circuit below, the electromotive force generated by the battery is e = 6.0 v, and the resistances are r1 = r4 = 1.0 q, r2 = r3 =2.0 q. r. the power delivered by the battery to the circuit is closest to a. 6 w в. 12 w с. 15 w d. 18 w e. 20 w final exam autumn 2014 page 5 of 9 68037 physical modelling faculty of science [2 mark] question 8 with reference to question 7, the current through resistor r2 is closest to a. 1 a в. 2 а c. 3 a d. 4 a e. 6 a

Acar travels 40m in 8 seconds find the car speed

Glass has a hardness that is in the middle of the hardness scale. what is the hardness of glass?