In a laser
a. light is amplified by stimulated emission of radiation.
b. the emitted light is monochromatic.
c. the emitted light is coherent.
d. there is a population inversion of electrons in atoms.
e. all of the above
e
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Total Internal Reflection: A tank holds a layer of oil, of thickness To = 1.65 m, that floats on a layer of syrup of thickness Ts = 0.830 m, as shown in the figure. Both liquids are clear and do not mix together. A light ray, originating at the bottom of the tank at point P, crosses the oil-syrup interface at a point 0.900 m from the axis. The ray continues and arrives at the oil-air interface, 2.00 m to the right of P and at the critical angle. What is the index of refraction of the syrup?
A. 1.36 B. 1.25 C. 1.94 D. 1.75 E. 1.54
Which of the following hypothetical observations would demonstrate that the inflation model was incorrect?
A) The geometry of the universe is curved, not flat. B) The helium abundance in a galaxy is 29%. C) The rate of expansion of the universe has changed over time. D) Stars began to shine only a few hundred million years after the Big Bang.
An electron is in an infinite square well that is 2.6 nm wide. What is the smallest value of the state quantum number n for which the energy level exceeds 100 eV? (h = 6.626 × 10-34 J ? s, mel = 9.11 × 10-31 kg, 1 eV = 1.60 × 10-19)
A) 43 B) 44 C) 45 D) 42 E) 41
A uniformly charged rod (length = 2.0 m, charge per unit length = 3.0 nC/m) is bent to form a semicircle. What is the magnitude of the electric field at the center of the circle?
a. 64 N/C b. 133 N/C c. 48 N/C d. 85 N/C e. 34 N/C