The temperature coefficient of resistivity of iron is 5.0 × 10^-3 / °C; that of carbon is -0.50 × 10^-3 / °C. When an iron wire and a carbon rod, each having the same 10 W resistance at 20°C, are cooled from that temperature to -80°C, the new ratio of the resistance of the carbon rod to the resistance of the iron wire at the lower temperature is
a. -0.10.
b. +1.9.
c. +2.1.
d. -10.
e. +10.
C
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Conduction: Two metal rods are to be used to conduct heat from a region at 100°C to a region at 0°C as shown in the figure. The rods can be placed in parallel, as shown on the left, or in series, as on the right. When steady state flow is established, the heat conducted in the series arrangement is
A. greater than the heat conducted with the rods in parallel. B. the same as the heat conducted with the rods in parallel. C. less than the heat conducted with the rods in parallel.
If M = 2.0 kg, what is the tension in string 1?
A. 1.2 N B. 11 N C. 34 N D. 3.5 N E. 40 N
The Cassini space probes used electricity provided by __________
Fill in the blank(s) with correct word
Three identical 3.0-kg cubes are placed on a horizontal surface in contact with one another. The cubes are lined up from left to right and an 18-N force is applied to the left side of the left cube causing all three cubes to accelerate to the right. If the cubes are each subject to a frictional force of 3.0 N, what is the magnitude of the force exerted on the middle cube by the left cube in this
case? a. 18 N c. 12 N b. 6 N d. none of the above