Domanda del libro di testo
What is the wavelength, in nm, of a photon with energy (a) 0.30 eV, (b) 3.0 eV, and (c) 30 eV? For each, is this wavelength visible, ultraviolet, or infrared light?
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Ch 38: Quantization
Knight Calc5th EditionPhysics for Scientists and EngineersISBN: 9780137344796
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TOC.tableOfContents
- Ch 01: Concepts of Motion35
- Ch 02: Kinematics in One Dimension75
- Ch 03: Vectors and Coordinate Systems58
- Ch 04: Kinematics in Two Dimensions60
- Ch 05: Force and Motion23
- Ch 06: Dynamics I: Motion Along a Line53
- Ch 07: Newton's Third Law27
- Ch 08: Dynamics II: Motion in a Plane52
- Ch 09: Work and Kinetic Energy56
- Ch 10: Interactions and Potential Energy50
- Ch 11: Impulse and Momentum56
- Ch 12: Rotation of a Rigid Body71
- Ch 13: Newton's Theory of Gravity52
- Ch 14: Fluids and Elasticity44
- Ch 15: Oscillations55
- Ch 16: Traveling Waves37
- Ch 17: Superposition39
- Ch 18: A Macroscopic Description of Matter53
- Ch 19: Work, Heat, and the First Law of Thermodynamics60
- Ch 20: The Micro/Macro Connection53
- Ch 21: Heat Engines and Refrigerators34
- Ch 22: Electric Charges and Forces40
- Ch 23: The Electric Field39
- Ch 24: Gauss' Law32
- Ch 25: The Electric Potential63
- Ch 26: Potential and Field57
- Ch 27: Current and Resistance42
- Ch 28: Fundamentals of Circuits39
- Ch 29: The Magnetic Field47
- Ch 30: Electromagnetic Induction60
- Ch 31: Electromagnetic Fields and Waves32
- Ch 32: AC Circuits63
- Ch 33: Wave Optics32
- Ch 34: Ray Optics57
- Ch 35: Optical Instruments30
- Ch 36: Special Relativity38
- Ch 37: The Foundations of Modern Physics25
- Ch 38: Quantization49
- Ch 39: Wave Functions and Uncertainty31
- Ch 40: One-Dimensional Quantum Mechanics35
- Ch 41: Atomic Physics18
- Ch 42: Nuclear Physics27
Knight Calc5th EditionPhysics for Scientists and EngineersISBN: 9780137344796Non è quello che usi tu?Cambia libro di testo
Capitolo 38, Problema 6a
A photoelectric-effect experiment finds a stopping potential of 1.56 V when light of 200 nm is used to illuminate the cathode. From what metal is the cathode made?
Guida verificata passo dopo passo1
Determine the energy of the incident photons using the equation for photon energy: \( E = \frac{hc}{\lambda} \), where \( h \) is Planck's constant (\( 6.626 \times 10^{-34} \, \text{J·s} \)), \( c \) is the speed of light (\( 3.00 \times 10^8 \, \text{m/s} \)), and \( \lambda \) is the wavelength of the light (200 nm, converted to meters as \( 200 \times 10^{-9} \)).
Convert the photon energy from joules to electron volts (eV) using the conversion factor \( 1 \text{ eV} = 1.602 \times 10^{-19} \, \text{J} \).
Relate the stopping potential \( V_s \) to the maximum kinetic energy of the ejected electrons using the equation \( K_{\text{max}} = eV_s \), where \( e \) is the elementary charge (\( 1.602 \times 10^{-19} \, \text{C} \)) and \( V_s = 1.56 \, \text{V} \).
Use the photoelectric equation \( E = \phi + K_{\text{max}} \), where \( \phi \) is the work function of the metal, \( E \) is the photon energy, and \( K_{\text{max}} \) is the maximum kinetic energy of the ejected electrons. Rearrange to solve for \( \phi \): \( \phi = E - K_{\text{max}} \).
Compare the calculated work function \( \phi \) (in eV) to known work functions of metals to identify the material of the cathode.
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Concetti chiave
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Photoelectric Effect
The photoelectric effect is the phenomenon where electrons are emitted from a material (usually a metal) when it absorbs light of sufficient energy. This effect demonstrates the particle nature of light, as photons must have a minimum energy, known as the work function, to dislodge electrons from the material.
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Percorso guidato
07:40
The Doppler Effect
Stopping Potential
Stopping potential is the minimum voltage needed to stop the flow of photoelectrons emitted from a cathode in a photoelectric experiment. It is directly related to the kinetic energy of the emitted electrons, which can be calculated using the equation eV = KE, where e is the charge of the electron, V is the stopping potential, and KE is the kinetic energy of the electrons.
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Percorso guidato
07:12Distance to Stop a Point Charge
Work Function
The work function is the minimum energy required to remove an electron from the surface of a metal. It is a characteristic property of each metal and is crucial in determining whether the energy of incoming photons (from light) is sufficient to overcome this barrier, thus allowing the photoelectric effect to occur.
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Percorso guidato
08:30Intro to Wave Functions
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