The document discusses factors that affect photoelectric emission from metals.
1) Photoelectric emission only occurs when light has a frequency above the metal's cutoff frequency. The type of metal determines the cutoff frequency.
2) Light intensity does not affect whether emission occurs, only the frequency relative to the cutoff matters.
3) Increasing light intensity increases the rate of electron emission for frequencies above the cutoff.
The document discusses the photoelectric effect and calculations related to photon energy. It begins by defining the formula for energy per photon as E=hf, where E is energy, h is Planck's constant, and f is frequency. It then works through examples of calculating the energy of photons with different wavelengths and frequencies incident on various metals. The key points are that photon energy must exceed the work function (W0) of the metal for photoelectric emission to occur, and the kinetic energy of the emitted electrons is equal to the photon energy minus the work function. The document also notes that photon frequency determines the possibility and rate of photoelectric emission from a metal, while intensity affects the emission rate.
Fundamentals of modern physics by imran azizDr.imran aziz
The document discusses several key concepts in modern physics including:
1) Classical relativity and reference frames in Newtonian physics.
2) The Michelson-Morley experiment and failures to detect the luminiferous ether.
3) Einstein's theory of special relativity and concepts like simultaneity, time dilation, and length contraction.
4) Wave-particle duality of light and matter like electrons.
The document discusses the photoelectric effect and Einstein's explanation of it using photon theory.
1) The photoelectric effect occurs when light shines on certain metals and generates an electric current. Classical physics could not explain observations that the current depends on frequency, not intensity, of light.
2) Einstein proposed that light consists of discrete packets of energy called photons. Photons can transfer their entire energy to eject electrons from a metal surface, but only if they have enough energy to overcome the metal's work function.
3) Einstein's explanation accounted for key observations, like the current dependence on frequency alone and a threshold frequency below which no current occurs regardless of intensity. It established light's particle-like properties and
The document discusses the photoelectric effect and provides details on several key topics:
1. It outlines 5 main subtopics to be covered in the chapter, including how the intensity and frequency of light affects photoelectrons and the quantitative equations involved.
2. It describes the photoelectric effect as the emission of electrons from a metal surface when light shines on it. Experimental results showed inconsistencies with the wave theory of light.
3. Einstein's photon theory predicted the kinetic energy of ejected electrons would increase linearly with frequency, in agreement with experiments, resolving discrepancies with the wave theory.
1) The document discusses the classical theory of electromagnetic radiation confined within an isothermal enclosure and the discrepancies with experimental observations.
2) It analyzes the temperature dependence of the energy density and pressure of the radiation using thermodynamic considerations.
3) This leads to the derivation of the Stefan-Boltzmann law relating the emissive power of a black body to the fourth power of its temperature.
11. ตัว อย่า งการหาคำา ตอบ
และแสดง
วิธ ี
แก้ส มการ
จงหาคำาตอบของ a + 12= 25
วิธีทำา
a + 12= 25
นำา 12 ลบทั้งสองข้างของสมการ
a + 12 – 12 = 25 – 12
a = 13
ตอบ
๑๓
12. จงหาคำา ตอบของ
สมการต่อ ไปนี้
1. 68 – a =
26 , a =
2. 27 + b =
92 , b =
3. c + 45 =
99 , c =
4. d - 22 =
26 , d =
60
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