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Direct the light reflected by the mirror on to a sheet of paper held close to the mirror. Move the sheet of paper back and forth gradually until you find on the paper sheet a bright, sharp spot of light. Hold the mirror and the paper in the same position for a few minutes.
- 11.4 EXPERIMENTAL STUDY OF PHOTOELECTRIC EFFECT
- 11.4.2 Effect of potential on photoelectric current
- SUMMARY
- POINTS TO PONDER
Figure 11.1 depicts a schematic view of the arrangement used for the experimental study of the photoelectric effect. It consists of an evacuated glass/quartz tube having a thin photosensitive plate C and another metal plate A. Monochromatic light from the source S of sufficiently short wavelength passes through the window W and falls on the photos...
We first keep the plate A at some positive potential with respect to the plate C and illuminate the plate C with light of fixed frequency n and fixed intensity I 1. We next vary the positive potential of plate A gradually and measure the resulting photocurrent each time. It is found that the photoelectric current increases with increase in positiv...
The minimum energy needed by an electron to come out from a metal surface is called the work function of the metal. Energy (greater than the work function fo) required for electron emission from the metal surface can be supplied by suitably heating or applying strong electric field or irradiating it by light of suitable frequency. Photoelectric ef...
Free electrons in a metal are free in the sense that they move inside the metal in a constant potential (This is only an approximation). They are not free to move out of the metal. They need additional energy to get out of the metal. Free electrons in a metal do not all have the same energy. Like molecules in a gas jar, the electrons have a certain...
A light beam or beam of light is a directional projection of light energy radiating from a light source.Sunlight forms a light beam (a sunbeam) when filtered through media such as clouds,foliage, or windows. A group of parallel rays is called a beam of light. It is also called a pencil of light.
Following are the important properties of light –. Light travels in a straight line. The speed of light is faster than sound. Light travels at a speed of 3 x 10 8 m/s. Reflection of light. Reflection is the phenomenon in which light travelling in one medium, incident on the surface of another returns to the first medium, obeying the laws of ...
Light is absorbed (propagation is stopped) Medium is opaque. If light wave frequency ≠ molecules resonant frequency. Light is reradiated and propagated forward through medium. Medium is transparent. In a solid or liquid, propagation is in straight line. In a gas, propagation is less organized and scatter increases.
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Apr 19, 2024 · ICSE Class 9 Selina Physics Book: Chapter-Wise PDF. In Concise Selina Physics for ICSE Class 9, there is a total of ten chapters. They start from the basics like SI units and other parts required ...
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What are the properties of light?
What are the laws of reflection?
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What are the laws of refraction?
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Why are different theories on the nature of light proposed?
When light propagates in a transparent material medium, its speed is in general less than the speed in vacuum c. An interesting consequence of this is that a light ray will change direction when passing from one medium to another. Since the light ray appears to be “broken”, the phenomenon is known as refraction.
