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PH-101 Introductory Physics Assignment #3 (Chap 27, 29, 30, 31) Date: 09-05-2011 Submission Date: 16-05-2011
1) A solid cube of silver (density = 10.5 g/cm3) has a mass of 90.0 g. (a) what is the resistance between opposite faces of the cube? (b) Assume each silver atom contributes one conduction
electron. Find the average drift speed of electrons when a potential difference of 1.00 × 10 -5
applied to opposite faces. The atomic number of silver is 47, and its molar mass is 107.87 g/mol.
2) Material with uniform resistivity ρ is formed into a wedge as shown in Figure.1. Show that the resistance between face A and face B of this wedge is
Figure.1 3) In Figure.2, the cube is 40.0 cm on each edge. Four straight segments of wire —ab, bc, cd, and
da— form a closed loop that carries a current I = 5.00 A, in the direction shown. A uniform
magnetic field of magnitude B = 0.0200 T is in the positive y direction. Determine the magnitude
and direction of the magnetic force on each segment.
Figure.2 4) A conductor suspended by two flexible wires as shown in Figure.3 has a mass per unit length of
0.040 0 kg/m. What current must exist in the conductor in order for the tension in the supporting
wires to be zero when the magnetic field is 3.60 T into the page? What is the required direction
for the current?
5) For the system of capacitors shown in Figure.4, find (a) the equivalent capacitance of the system,
(b) the potential across each capacitor, (c) the charge on each capacitor?
6) In Figure.5, the bar magnet is moved toward the loop. Is Va-Vb positive, negative, or zero? Explain.
7) The plane of a square loop of wire with edge length a = 0.200 m is perpendicular to the Earth’s magnetic field at a point where B = 15.0 μT, as shown in Figure.6 The total resistance of the loop
and the wires connecting it to a sensitive ammeter is 0.500 Ω If the loop is suddenly collapsed by
horizontal forces as shown, what total charge passes through the ammeter?