# College Physics

Physics & Astronomy

## Quiz 13 : Quantum Physics Looking for Introductory Physics Homework Help?

## Quiz 13 :Quantum Physics

Question Type  If you observe objects inside a very hot kiln, why is it difficult to discern the shapes of the objects
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The light reflection from the object surface is observed to determine the shape of the object. The objects inside a kiln will be very hot and are shining with brilliant red. So, the radiation emitted from the object is much stronger than the reflected radiation. The collection of objects inside kiln including walls of kiln, shining equally with emitted radiation and also reflected light is weak as compared to the emitted radiation. As a result, we cannot observe the objects inside a hot kiln.

Tags (a) What is the surface temperature of Betelgeuse, a red giant star in the constellation of Orion, which radiates with a peak wavelength of about 970 nm (b) Rigel, a bluish-white star in Orion, radiates with a peak wavelength of 145 nm. Find the temperature of Rigel's surface
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(a)
The expression for peak wavelength of radiation given by Wien's displacement law, Here, is the surface temperature of star.
Rearrange the equation for . Convert the unit of from nm to m, Substitute for in the equation and solve for . Round off to one significant figure, the surface temperature of red giant star is .
(b)
Use Wein's displacement law, the surface temperature of the bluish-white star is as follows. Convert the unit of from nm to m, Substitute for in the equation and solve for . Round off to one significant figure, the surface temperature of the bluish-white star is .

Tags Why is an electron microscope more suitable than an optical microscope for "seeing" objects of atomic size
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A microscope can be used to see the details of smaller object which is less than the wavelength of the light waves. Electrons are moving with a kinetic energy of several electron volts whose wavelengths less than a nanometer. This wavelength is much smaller than the wavelengths of visible light. So, the particles with much smaller size can be resolved by using electron microscope whereas compared with the optical microscope.

Tags (a) Lightning produces a maximum air temperature on the order of 10 4 K, whereas (b) a nuclear explosion produces a temperature on the order of 10 7 K. Use Wien's displacement law to find the order of magnitude of the wavelength of the thermally produced photons radiated with greatest intensity by each of these sources. Name the part of the electromagnetic spectrum where you would expect each to radiate most strongly
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Tags Are blackbodies black
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Tags The temperature of a student's skin is 33.0°C. At what wavelength does the radiation emitted from the skin reach its peak
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Tags Why is it impossible to simultaneously measure the position and velocity of a particle with infinite accuracy
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Tags The radius of our Sun is 6.96 × 10 8 m, and its total power output is 3.85 × 10 26 W. (a) Assuming the Sun's surface emits as a black body, calculate its surface temperature. (b) Using the result of part (a), find max for the Sun
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Tags All objects radiate energy. Why, then, are we not able to see all the objects in a dark room
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Tags Calculate the energy in electron volts of a photon having a wavelength (a) in the microwave range, 5.00 cm, (b) in the visible light range, 500 nm, and (c) in the x-ray range, 5.00 nm
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Tags Is light a wave or a particle Support your answer by citing specific experimental evidence.
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Tags Suppose a star with radius 8.50 × 10 8 m has a peak wavelength of 685 nm in the spectrum of its emitted radiation. (a) Find the energy of a photon with this wavelength. (b) What is the surface temperature of the star (c) At what rate is energy emitted from the star in the form of radiation Assume the star is a blackbody ( e = 1). (d) Using the answer to part (a), estimate the rate at which photons leave the surface of the star.
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Tags In the photoelectric effect, explain why the stopping potential depends on the frequency of the light but not on the intensity.
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Tags Calculate the energy, in electron volts, of a photon whose frequency is (a) 620 THz (b) 3.10 GHz (c) 46.0 MHz
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Tags Which has more energy, a photon of ultraviolet radiation or a photon of yellow light
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Tags The threshold of dark-adapted (scotopic) vision is 4.0 × 10 11 W/m 2 at a central wavelength of 500 nm. If light with this intensity and wavelength enters the eye when the pupil is open to its maximum diameter of 8.5 mm, how many photons per second enter the eye
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Tags Why does the existence of a cutoff frequency in the photoelectric effect favor a particle theory of light rather than a wave theory
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Tags When light of wavelength 350 nm falls on a potassium surface, electrons having a maximum kinetic energy of 1.31 eV are emitted. Find (a) the work function of potassium, (b) the cutoff wavelength, and (c) the frequency corresponding to the cutoff wavelength
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