Terminal Voltage and Internal Resistance: A battery has an emf ? = 78.0 V and an internal resistance r = 4.0 ?, as shown in the figure. A current of 4.7 A is drawn from the battery when a resistor R is connected across the terminals a and b. The power dissipated by the resistor R is closest to
A. 280 W.
B. 340 W.
C. 320 W.
D. 300 W.
E. 370 W.
Answer: A
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Molecular Speeds: A sealed container holds 0.020 moles of ideal nitrogen (N2) gas, at a pressure of 1.5 atm and a temperature of 290 K. The atomic mass of nitrogen is 14.0 g/mol. What is the average translational kinetic energy of a nitrogen molecule? The Boltzmann constant is 1.38 × 10-23 J/K.
A. 4.0 × 1021 J B. 6.0 × 1021 J C. 8.0 × 1021 J D. 10 × 1021 J E. 12 × 1021 J
A long wire carries a current toward the north in a magnetic field that is directed vertically downward. What is the direction of the magnetic force on the wire?
a) west b) north c) east d) vertically upward e) vertically downward
Redshift measurements of the visible afterglow of a gamma-ray burst show that these objects are:
A) in the solar neighborhood. B) in the Milky Way Galaxy. C) in the Local Group. D) billions of light-years away. E) at the most extreme observable distances.
A 90.0 kg person is running up the stairs at 0.500 m/s. The power needed to run up the stairs is
A. 441 Watts. B. 395 Watts. C. 302 Watts. D. 275 Watts. E. 257 Watts.