Why are radio frequency waves not very penetrating? Give two safety precautions you should take when using a mobile phone. A narrow beam of light undergoes dispersion when it passes through either a prism or a diffraction grating. What is meant by dispersion? (6) Give two differences between what is observed when a narrow beam of light undergoes dispersion as it passes through a prism, and what is observed when a narrow beam of light undergoes dispersion as it passes through a diffraction grating. (6) Give another example of light undergoing dispersion. (4) Yellow light of wavelength 589 nm is produced in a low-pressure sodium vapour lamp. What causes the sodium atoms to emit this light? (3) Calculate the highest order image that could be produced when a beam of light of this wavelength is incident perpendicularly on a diffraction grating that has 300 lines per mm. (9) Mandatory Experiments 1: An interference pattern is formed on a screen when green light from a laser passes normally through a diffraction grating. The grating has 80 lines per mm and the distance from the grating to the screen is 90 cm. The distance between the third order images is 23.8 cm. Calculate the wavelength of the green light. Calculate the maximum number of images that are formed on the screen. The laser is replaced with a source of white light and a series of spectra are formed on the screen. Explain how the diffraction grating produces a spectrum. Explain why a spectrum is not formed at the central (zero order) image. 2: You carried out an experiment to measure the wavelength of a monochromatic light source using a diffraction grating. The diffraction grating had 600 lines per mm. Draw a labelled diagram of the apparatus you used. Name a source of monochromatic light. State what measurements you took during the experiment. What is the distance between each line on the diffraction grating? How did you determine the wavelength of the light? Give one precaution that you took to get an accurate result. 3: You carried out an experiment to measure the wavelength of a monochromatic light source. Name a monochromatic light source. Draw a labelled diagram of the apparatus that you used in the experiment. What readings did you take during the experiment? What formula did you use to calculate the wavelength of the light? Give one precaution that you took to get an accurate result. 4:
Why are radio frequency waves not very penetrating? Give two safety precautions you should take when using a mobile phone. A narrow beam of light undergoes dispersion when it passes through either a prism or a diffraction grating. What is meant by dispersion? (6) Give two differences between what is observed when a narrow beam of light undergoes dispersion as it passes through a prism, and what is observed when a narrow beam of light undergoes dispersion as it passes through a diffraction grating. (6) Give another example of light undergoing dispersion. (4) Yellow light of wavelength 589 nm is produced in a low-pressure sodium vapour lamp. What causes the sodium atoms to emit this light? (3) Calculate the highest order image that could be produced when a beam of light of this wavelength is incident perpendicularly on a diffraction grating that has 300 lines per mm. (9) Mandatory Experiments 1: An interference pattern is formed on a screen when green light from a laser passes normally through a diffraction grating. The grating has 80 lines per mm and the distance from the grating to the screen is 90 cm. The distance between the third order images is 23.8 cm. Calculate the wavelength of the green light. Calculate the maximum number of images that are formed on the screen. The laser is replaced with a source of white light and a series of spectra are formed on the screen. Explain how the diffraction grating produces a spectrum. Explain why a spectrum is not formed at the central (zero order) image. 2: You carried out an experiment to measure the wavelength of a monochromatic light source using a diffraction grating. The diffraction grating had 600 lines per mm. Draw a labelled diagram of the apparatus you used. Name a source of monochromatic light. State what measurements you took during the experiment. What is the distance between each line on the diffraction grating? How did you determine the wavelength of the light? Give one precaution that you took to get an accurate result. 3: You carried out an experiment to measure the wavelength of a monochromatic light source. Name a monochromatic light source. Draw a labelled diagram of the apparatus that you used in the experiment. What readings did you take during the experiment? What formula did you use to calculate the wavelength of the light? Give one precaution that you took to get an accurate result. 4: