1. What is the nature of radiation?
When radiation travels through an aperture or an edge, it has the property of bending. Only if the radiation has a wave character can it be bent. Radiation beams or rays change direction when they strike a reflecting surface or an optically denser medium, as seen by reflection and refraction. It doesn't explain the radiations' particle nature. The photoelectric effect of radiation states that when a photon of radiation collides with a metal surface, if the photon's energy is above the metal's threshold energy, electrons are emitted. Radiations are shown as a packet of energy or a particle with one phonon energy in this effect. Hence, the properties of photoelectric effect and diffraction explain the dual nature of radiation.
2. What were the observations made by Hertz and Lenard on the photoelectric effect?
As mentioned in dual nature of radiation and matter class 12 NCERT solutions, in 1887, Heinrich Hertz discovered that when light falls on a metal surface, certain electrons near the surface absorb enough energy from the incoming radiation to overcome the attraction of the positive ions in the surface material.
3. How many subtopics are included in the dual nature of radiation and matter chapter of class 12 physics?
The following are the subtopics in dual nature NCERT solutions:
- Electron Emission
- Photoelectric Effect
- Hertz’s observations
- Hallwachs’ and Lenard’s observations
- Experimental Study Of Photoelectric Effect
- Effect of intensity of light on photocurrent
- Effect of potential on photoelectric current
- Effect of frequency of incident radiation on stopping potential
- Photoelectric Effect and Wave Theory of Light Ex
- Einstein’s Photoelectric Equation: Energy Quantum of Radiation
- Particle Nature of Light: The Photon
- Wave Nature of Matter
4. What is the photoelectric effect in Chapter 11 of NCERT Solutions for Class 12 Physics?
As mentioned in NCERT solutions for class 12 physics chapter 11, the photoelectric effect is the phenomenon of electrons emitting from a metal's surface when a sufficient frequency of light falls on it.
Other related concepts given in dual nature of matter and radiation NCERT solutions include the following:
- Photoelectrons are expelled electrons.
- The photocurrent is the current generated by released electrons.