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प्रश्न
In the case of a photo electric effect experiment, explain the following facts, giving reasons.
The wave theory of light could not explain the existence of the threshold frequency.
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उत्तर
If light were strictly a wave, the energy in the light would be represented by the amplitude of the light wave. A more intense light source, even if it were of a lower frequency, would have enough energy to knock out electrons away from the metal surface, which is necessary to generate a photoelectric current.
What actually occurs is that the light below a certain threshold frequency does not generate any current, no matter how intense the light is.
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संबंधित प्रश्न
Is the formula you employ in (a) valid for calculating radius of the path of a 20 MeV electron beam? If not, in what way is it modified?
Define the term "cut off frequency" in photoelectric emission. The threshod frequency of a metal is f. When the light of frequency 2f is incident on the metal plate, the maximum velocity of photo-electrons is v1. When the frequency of the incident radiation is increased to 5f, the maximum velocity of phto-electrons is v2. Find the ratio v1 : v2.
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(Use h = 6.63 × 10-34J-s = 4.14 × 10-15 eV-s, c = 3 × 108 m/s and me = 9.1 × 10-31kg)
A silver ball of radius 4.8 cm is suspended by a thread in a vacuum chamber. Ultraviolet light of wavelength 200 nm is incident on the ball for some time during which light energy of 1.0 × 10−7 J falls on the surface. Assuming that on average, one photon out of every ten thousand is able to eject a photoelectron, find the electric potential at the surface of the ball, assuming zero potential at infinity. What is the potential at the centre of the ball?
(Use h = 6.63 × 10-34J-s = 4.14 × 10-15 eV-s, c = 3 × 108 m/s and me = 9.1 × 10-31kg)
In Photoelectric effect ______.
In photoelectric effect, the photoelectric current
What do free electrons at the surface of a metal do when radiation falls on the surface, according to the wave picture?
According to wave theory, how should greater radiation intensity affect the energy absorbed by each electron?
What does wave theory predict about the existence of a threshold frequency?
Which wave-theory prediction about maximum kinetic energy contradicts the observed features of photoelectric emission?
