A resistor of unknown resistance and a 15-W resistor are connected across a 20-V emf in such a way that a 2.0 A current is observed in the emf. What is the value of the unknown resistance?
a. 75 W
b. 12 W
c. 7.5 W
d. 30 W
e. 5.0 W
D
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Which is a distinguishing characteristic of the Jovian planets? a. Jovian planets are rocky
b. Jovian planets are geologically inactive. c. Jovian planets have rings. d. Jovian planets have only one or two moons. e. Jovian planets have high albedos.
Which of the following statements does not describes the similarity between soaps and detergents?
A) They have a polar ionic end and a long nonpolar tail. B) Both dissolve oils. C) Both are synthetic. D) Both are biodegradable. E) Both are made from fatty acids.
Assume that a certain city consumes electrical energy at an average rate of 2.0 × 109 W. What would be the mass change in producing enough energy to keep this city running for 21 weeks? (c = 3.00 × 108 m/s)
A) 0.28 kg B) 0.32 kg C) 0.39 kg D) 0.48 kg
The energy of the ground state in the Bohr model of the hydrogen atom is -13.6 eV. In a transition from the n = 2 state to the n = 4 state, a photon of energy
A) 3.40 eV is emitted. B) 3.40 eV is absorbed. C) 2.55 eV is emitted. D) 2.55 eV is absorbed. E) 0.85 eV is absorbed.