## College Physics

Physics & Astronomy

## Quiz 28 :

Quantum Physics

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Q01 Q01 Q01

Two sources emit beams of microwaves. The microwaves from source A have a frequency of 10 GHz, and the ones from source B have a frequency of 20 GHz. This is all we know about the two beams. Which of the following statements about these beams are correct? (There could be more than one correct choice.)

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B

Q02 Q02 Q02

Two sources emit beams of light of wavelength 550 nm. The light from source A has an intensity of 10 µW/m

^{2}, and the light from source B has an intensity of 20 µW/m^{2}. This is all we know about the two beams. Which of the following statements about these beams are correct? (There could be more than one correct choice.)Free

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A

Q08 Q08 Q08

Monochromatic light is incident on a metal surface, and the ejected electrons give rise to a current in the circuit shown in the figure. The maximum kinetic energy of the ejected electrons is determined by applying a reverse ('stopping')potential, sufficient to reduce the current in the ammeter to zero. If the intensity of the incident light is increased, how will the required stopping potential change?

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Q19 Q19 Q19

A researcher is using x-rays to investigating a cubic crystal. He is looking at Bragg reflection from the planes parallel to the cube faces. He finds that when using x-rays with a wavelength of 0.165 nm, a strong first maximum occurs when the beam makes an angle of 23.5° with the planes. What is the spacing of adjacent atoms in this crystal?

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Q20 Q20 Q20

Certain planes of a crystal of halite have a spacing of 0.399 nm. The crystal is irradiated by a beam of x-rays. First order constructive interference occurs when the beam makes an angle of 20° with the planes of the crystal surface. What is the wavelength of the x-rays?

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Q21 Q21 Q21

Certain planes of a crystal of halite have a spacing of 0.399 nm. The crystal is irradiated by a beam of x-rays. First order constructive interference occurs when the beam makes an angle of 20° with the planes of the crystal surface. What angle does the beam make with the crystal planes for second order constructive?

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Q34 Q34 Q34

A metallic surface is illuminated with light of wavelength 400 nm. If the work function for this metal is 2.40 eV, what is the maximum kinetic energy of the ejected electrons, in electron-volts? (1 eV = 1.60 × 10

^{-19}J, c = 3.00 × 10^{8}m/s, h = 6.626 × 10^{-34}J ∙ s)Free

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Q41 Q41 Q41

Light with a wavelength of 310 nm is incident on a metal that has a work function of 3.80 eV. What is the maximum kinetic energy that a photoelectron ejected in this process can have? (1 eV = 1.60 × 10

^{-19}J, c = 3.00 × 10^{8}m/s, h = 6.626 × 10^{-34}J ∙ s)Free

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Q44 Q44 Q44

A beam of light with a frequency range from 3.01 × 10

^{14}Hz to 6.10 × 10^{14}Hz is incident on a metal surface. If the work function of the metal surface is 2.20 eV, what is the maximum kinetic energy of photoelectrons ejected from this surface? (h = 6.626 × 10^{-34}J ∙ s, 1 eV = 1.60 × 10^{-19}J)Free

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Q48 Q48 Q48

A photocathode whose work function is 2.9 eV is illuminated with white light that has a continuous wavelength band from 400 nm to 700 nm. What is the range of the wavelength band in this white light illumination for which photoelectrons are not produced?(c = 3.00 × 10

^{8}m/s, h = 6.626 × 10^{-34}J ∙ s, 1 eV = 1.60 × 10^{-19}J)Free

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Q50 Q50 Q50

A photocathode having a work function of 2.4 eV is illuminated with monochromatic light whose photon energy is 3.4 eV. What is maximum kinetic energy of the photoelectrons produced?(c = 3.00 × 10

^{8}m/s, h = 6.626 × 10^{-34}J ∙ s, 1 eV = 1.60 × 10^{-19}J)Free

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Q51 Q51 Q51

A photocathode having a work function of 2.8 eV is illuminated with monochromatic electromagnetic radiation whose photon energy is 4.0 eV. What is the threshold (cutoff)frequency for photoelectron production? (1 eV = 1.60 × 10

^{-19}J, h = 6.626 × 10^{-34}J ∙ s)Free

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Q53 Q53 Q53

When a photoelectric surface is illuminated with light of wavelength 437 nm, the stopping potential is measured to be 1.67 V. (1 eV = 1.60 × 10

^{-19}J, e = 1.60 × 10^{-19}C, m_{electron}= 9.11 × 10^{-31}kg, h = 6.626 × 10^{-34}J ∙ s) (a)What is the work function of the metal, in eV? (b)What is the maximum speed of the ejected electrons?Free

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Q54 Q54 Q54

In her physics laboratory, Mathilda shines electromagnetic radiation on a material and collects photoelectric data to determine Planck's constant. She measures a stopping potential of 5.82 V for radiation of wavelength 100 nm, and 17.99 V for radiation of wavelength 50.0 nm. (1 eV = 1.60 × 10

^{-19}J, c = 3.00 × 10^{8}m/s) (a)Using Mathilda's data, what value does she determine for Planck's constant? (b)What is the work function of the material Mathilda is using, in electron-volts?Free

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Q58 Q58 Q58

A monochromatic light beam is incident on the surface of a metal having a work function of 2.50 eV. If a 1.0-V stopping potential is required to make the electron current zero, what is the wavelength of light? (c = 3.00 × 10

^{8}m/s, h = 6.626 × 10^{-34}J ∙ s, 1 eV = 1.60 × 10^{-19}J)Free

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Q62 Q62 Q62

Atoms in crystals are typically separated by distances of 0.10 nm. What kinetic energy must a nonrelativistic electron have, in electron-volts, in order to have a wavelength of 0.10 nm? (m

_{electron}= 9.11 × 10^{-31}kg, 1 eV = 1.60 × 10^{-19}J, h = 6.626 × 10^{-34}J ∙ s)Free

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Q63 Q63 Q63

The electrons in a beam are moving at 18 m/s. (m

_{electron}= 9.11 × 10^{-31}kg, h = 6.626 × 10^{-34}J ∙ s) (a)What is its de Broglie wavelength these electrons? (b)If the electron beam falls normally on a diffraction grating, what would have to be the spacing between slits in the grating to give a first-order maximum at an angle of 30° with the normal to the grating?Free

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Q64 Q64 Q64

A proton that is moving freely has a wavelength of 0.600 pm. (m

_{proton}= 1.67 × 10^{-27}kg, e = 1.60 × 10^{-19}C, h = 6.626 × 10^{-34}J ∙ s) (a)What is its momentum? (b)What is its speed? (c)What potential difference would it have been accelerated through, starting from rest, to reach this speed?Free

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Q65 Q65 Q65

A crystal diffracts a beam of electrons, like a diffraction grating, as they hit it perpendicular to its surface. The crystal spacing is 0.18 nm, and the first maximum scattering occurs at 80° relative to the normal to the surface. (e = 1.60 × 10

^{-19}C, m_{electron}= 9.11 × 10^{-13}kg, h = 6.626 × 10^{-34}J ∙ s) (a)What is the wavelength of the electrons? (b)What potential difference accelerated the electrons if they started from rest?Free

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Q80 Q80 Q80

An electron is accelerated from rest through a potential difference. After acceleration the electron has a wavelength of 880 nm. What is the potential difference responsible for the acceleration of the electron? (h = 6.626 × 10

^{-34 }J ∙ s, m_{electron}= 9.11 × 10-31 kg, e = 1.6 10^{-19 }C)Free

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Q81 Q81 Q81

Electrons emerge from an electron gun with a speed of 2.0 × 10

^{6}m/s and then pass through a double-slit apparatus. Interference fringes with spacing of 2.7 mm are detected on a screen far from the double slit. What would the fringe spacing be if the electrons were replaced by neutrons with the same speed? (h = 6.626 × 10^{-34}J ∙ s, m_{electron}= 9.11 × 10^{-31}kg, m_{neutron}= 1.675 × 10^{-27}kg)Free

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Q82 Q82 Q82

Electrons are accelerated to a speed of 4.0 × m/s and are then aimed at a double-slit apparatus, where interference fringes are detected. If the electrons were replaced by neutrons, what speed must neutrons have to produce interference fringes with the same fringe spacing as that observed with the electrons? (h = 6.626 × 10

^{-34}J ∙ s, m_{electron}= 9.11 × 10^{-31}kg, m_{neutron}= 1.675 × 10^{-27}kg)Free

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Q83 Q83 Q83

Electrons with a speed of 2.1 × 10

^{6}m/s are directed towards a 1.0-μm wide slit. An electron detector is placed 1.0 m behind the slit. How wide is the central maximum of the electron diffraction pattern on the detector? (h = 6.626 × 10^{-34}J ∙ s, m_{electron}= 9.11 × 10^{-31}kg)Free

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Q84 Q84 Q84

A certain crystal has a spacing of 0.442 nm between atoms. A beam of neutrons moving with a speed of 1640 m/s perpendicular to the surface is diffracted as it passes through the crystal. What is the angle from the central maximum to the next interference maximum? (m

_{neutron}= 1.675 × 10^{-27}kg, h = 6.626 × 10^{-34}J ∙ s)Free

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Q85 Q85 Q85

The spacing of the atoms of a crystal is 159 pm. A monoenergetic beam of neutrons directed normally at the surface of the crystal undergoes first order diffraction at an angle of 58° from the normal. What is the energy of each of the neutrons? (m

_{neutron}= 1.675 × 10^{-27}kg, 1 eV = 1.6 × 10^{-19}J, h = 6.626 × 10^{-34}J ∙ s)Free

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