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प्रश्न
Give the applications photocell.
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उत्तर
Applications of photocells:
- Photocells have many applications, especially as switches and sensors.
- Automatic lights that turn on when it gets dark use photocells, as well as street lights that switch on and off according to whether it is night or day.
- Photocells are used for the reproduction of sound in motion pictures and are used as timers to measure the speeds of athletes during a race.
- Photocells are used to measure the intensity of the given light and to calculate the exact time of exposure.
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संबंधित प्रश्न
A photoelectric surface is illuminated successively by monochromatic light of wavelength λ and `λ/2`. If the maximum kinetic energy of the emitted photoelectrons in the second case is 3 times that in the first case, the work function of the material is
A light of wavelength 500 nm is incident on a sensitive metal plate of photoelectric work function 1.235 eV. The kinetic energy of the photoelectrons emitted is (Take h = 6.6 × 10–34 Js)
Give the definition of intensity of light according to quantum concept and its unit.
What is a surface barrier?
Explain the effect of potential difference on photoelectric current.
Explain how frequency of incident light varies with stopping potential.
Give the construction and working of photo emissive cell.
Calculate the energies of the photons associated with the following radiation:
- violet light of 413 nm
- X-rays of 0.1 nm
- radio waves of 10 m
How many photons of frequency 1014 Hz will make up 19.86 J of energy?
A 3310 Å photon liberates an electron from a material with energy 3 × 10−19 J while another 5000 Å photon ejects an electron with energy 0.972 × 10−19 J from the same material. Determine the value of Planck’s constant and the threshold wavelength of the material.
