A collection of atoms has 20% of the sample in a state 5.9 eV above the ground state
If these emit coherent radiation, what is the wavelength of the laser light produced? (c = 3.00 × 108 m/s,
h = 6.626 × 10-34 J ? s, 1 eV = 1.60 × 10-19 J)
A) 210 nm
B) 91 nm
C) 340 nm
D) 34 nm
A
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What happens to the frequency of the scattered X-rays beam as the scattering angle in the Compton effect decreases?
A) It stays the same. B) It decreases. C) It increases. D) Not enough information
A metal wire has a resistance of 10.00 W at a temperature of 20.0°C. If the same wire has a resistance of 10.55 W at 90°C, what is the resistance when its temperature is 0.0°C?
a. 13.8 W c. 9.84 W b. 9.69 W d. 0.70 W
Magnetic field lines come out of the south pole of a magnet and enter at the north pole
Indicate whether the statement is true or false
This diagram shows a person on a planet watching you travel to the right at 0.9c, while you have a flashlight turned on with the light shining to the right. Which of the following statements is not true from your point of view?
A) If you can increase your speed by another 0.1c, you'll be able to keep up with the flashlight beam. B) The person and planet are moving to your left at 0.9c. C) Time is running slow for the person on the planet. D) The light from the flashlight beam is moving to the right at the speed of light c.