Read the following statements about the photoelectric effect: 1. The kinetic energy of emitted photoelectrons increases with increasing intensity of incident light. 2. The photoelectric effect demonstrates the particle nature of light. 3. There is a threshold frequency below which no photoemission occurs, regardless of light intensity. Which of the above statements are correct?
2 and 3 only
Apply Einstein's photoelectric equation: \(KE_{max} = h\nu - \phi\), where \(h\nu\) is the photon energy and \(\phi\) is the work function.
Statement 1 (Wrong): The kinetic energy of emitted photoelectrons depends on the frequency of the incident light, not its intensity. Increasing intensity increases the number of emitted electrons, but not their kinetic energy.
Statement 2 (Correct): The photoelectric effect cannot be explained by the wave theory of light. Einstein's explanation in 1905 (using photons / quanta) demonstrated the particle nature of light.
Statement 3 (Correct): Photoemission occurs only if \(\nu \ge \nu_0\) (the threshold frequency, where \(h\nu_0 = \phi\)). Below this frequency, no electrons are emitted regardless of intensity.
Hence statements 2 and 3 only are correct.
Important Questions from Dual Nature: Photon and Matter Waves
In a photoelectric experiment, both sodium (work function = 2.3 eV) and tungsten (work function = 4.5 eV) metals are illuminated by an ultraviolet light of same wavelength. If the stopping potential for tungsten is measured to be 1.8 V, then the value of the stopping potential for sodium will be
Rapid electron acceleration and deceleration in a conducting wire can generate _______ with frequencies ranging from ______.
- The photoelectric current is directly proportional to the number of photo electrons emitted per second. This implies that
- The de-Broglie wavelength associated with a ball of mass 150 g traveling at 30.0 m/s would be
- A proton accelerated through a potential difference of V volts has a de-Broglie wavelength $\lambda$ associated with it. In order to get the same wavelength associated with an $\alpha$-particle, the required accelerating potential is
