AV Bapplied ******* AV Measuring properties of some material An experiment was carried out to determine the electrical properties of a new conducting material. A bar was made out of the material, L- 18 cm long with a rectangular cross section h-5 cm high and w-0.8 cm deep. The bar was part of a circuit and carried a steady current (the diagram shows only part of the circuit). A uniform magnetic field of 1.2 tesla was applied perpendicular to the bar, coming out of the page (using some coils that are not shown). Two voltmeters were connected along and across the bar as shown. The reading on Voltmeter 1 is av; - -0.45 volt. The reading on Voltmeter 2 is AV, - +0.00029 volt. The connections across the bar for Voltmeter 2 were carefully placed directly across from each other to eliminate false readings corresponding to the much larger voltage along the bar. There is only one kind of mobile charge in this material. Remember that a voltmeter gives a positive reading if the positive lead is connected to a higher potential location than the negative lead. (a) What is the sign of the mobile charges, and which way do they move? Positive mobile charges moving in (b) What is the drift speed v of the mobile charges? the x direction v m/s (c) What is the mobility u of the mobile charges? (m/s/(v/m) (d) The current running through the bar was measured to be 0.4 ampere. If each mobile charge is singly charged (lal- e), how many mobile charges are there in 1 m of this material? (e) What is the resistance in ohms of this length of bar? Additional Mates