Four identical point charges (+4.0 ?C) are placed at the corners of a square which has 20-cm sides. How much work is required to assemble this charge arrangement starting with each of the charges a very large distance from any of the other charges?
a. +2.9 J
b. +3.9 J
c. +2.2 J
d. +4.3 J
e. +1.9 J
b
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From Kepler's third law, an asteroid with an orbital period of 8 years lies at an average distance from the Sun equal to
A) 16 astronomical units. B) 4 astronomical units. C) 8 astronomical units. D) 2 astronomical units. E) It depends on the asteroid's mass.
A key component of one type of spectroscope for visible radiation is the
A) filter for separating the different gases. B) magnet for bending the radiation beam. C) electrostatic plate for bending and separating the radiation beam. D) prism for separating the radiation beam. E) mirror for separating the radiation beam.
A refrigerator has a coefficient of performance of 1.15, and it extracts 7.95 J of heat from the cold reservoir during each cycle
(a) How much work is done on the gas in each cycle? (b) How much heat is exhausted into the hot reservoir in each cycle?
The energy of an electron state has an uncertainty of 0.500 eV. What is the minimum uncertainty in the lifetime of the level? ( h = 1.055 × 10-34 J ? s = 6.591 × 10-16 eV ? s, 1 eV = 1.60 × 10-19 J)
A) 1.32 × 10-15 B) 1.32 × 10-8 C) 8.28 × 10-15 D) 8.28 × 10-11 E) 1.32 × 10-11