HSC Physics Photoelectric Effect

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A tutorial sheet of problems on the photoelectric effect follows.

  1. What factors determine the intensity of light shining on a surface?
  2. If the light shines at 30° to the surface of the metal does this change the number of photoelectrons released compared to when the light shines perpendicular to the surface?
  3. The frequency of light is increased but the intensity of the light is kept constant. Describe how this affects the rate at which electrons are released from the metal surface on which the light falls.
  4. Sketch a graph showing the maximum kinetic energy of the escaping photoelectrons versus the wavelength of the incident light.
  5. Why is the maximum kinetic energy calculated in the photoelectric effect? Do some escaping electrons have more kinetic energy than others?

IB Energy Topics

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A tutorial sheet on topic 8.1 energy sources and 8.2 thermal transfer is given below.

  1. The intensity of the Sun's radiation at the Earth's orbit is I. If the Earth's albedo is 𝛼 determine the average intensity over the surface of the entire Earth. [I(1-𝛼)/4]
  2. An Earth-like planet is discovered orbiting a distant star at an average distance of 2.7x1012m. If the power of the star is 1.3x1028W, calculate the surface temperature of the planet. Take the albedo and emissivity of the planet as 0.3 and 0.61 respectively. [163.7K]
  3. The solar constant is 1361 Wm-2. The albedo of the Earth is 0.33 and its emissivity is 0.61. Determine the surface temperature of the Earth if the albedo increases by 10% and the emissivity decreases by 10%. [292.5K]
  4. The solar constant is 1361 Wm-2 at the Earth's distance from the Sun. At what distance from the centre of the Sun is the solar constant 15 Wm-2? What planet is at this distance? [Saturn]
  5. A lake full of water has an area of 5.1x106m and a depth of 40 m. The base of the lake is 34 m above the turbine in a power station. Determine the greatest possible output power of the station if 1000 kg of water flows through it every second. [1.08x1014 W]
  6. In a nuclear power station 7.64x1019 fission reactions of U-235 occur per day. Each reaction releases 190 MeV of energy. Determine the specific energy and energy density of U-235. Assume that the sample is pure U-235 of density 19.1 gcm-3 and atomic mass 235.0439 u. [7.78x1013Jkg-1, 1.49x1018 Jm-3]
  7. In the previous question U-235 only occupies 3% by volume of the fuel rod which has a uniform density throughout. Determine the specific energy and energy density of the fuel rod.[2.33x1012,4.46x1016Jm-3]