Three ways to emit electronsइलेक्ट्रॉन उत्सर्जन के तीन तरीकेThree ways to emit electrons
NCERT Sec 11.2 · Class 12 Physics · Chapter 11 · interactive diagram
Read Chapter 11 with this diagramइस डायग्राम के साथ अध्याय 11 पढ़ेंIs diagram ke saath Ch 11 padhiyeAll Physics diagramsसभी भौतिकी डायग्रामSaare Physics diagrams
Parts and what they mean
- Thermionic emission (heat) (तापायनिक उत्सर्जन (ऊष्मा)) — Heating the metal gives free electrons enough thermal energy to come out (e.g. hot filament).
- Field emission (strong field) (क्षेत्र उत्सर्जन (प्रबल क्षेत्र)) — A very strong electric field (of the order of 10⁸ V m⁻¹) pulls electrons out of the metal, as in a spark plug.
- Electric field E (विद्युत क्षेत्र E) — Points from the + plate towards the metal (−); electrons feel a force opposite to E, so they are pulled out of the metal.
- Photoelectric emission (light) (प्रकाश-विद्युत उत्सर्जन (प्रकाश)) — Light of suitable (high enough) frequency falling on the metal ejects electrons — photoelectrons.
- Incident light (आपतित प्रकाश) — Its frequency must be above the threshold frequency of the metal.
- Emitted electron (उत्सर्जित इलेक्ट्रॉन) — Negatively charged; same e/m as cathode-ray particles, whichever way it was emitted.
Original diagram drawn by Simple Learning Hub, based on NCERT Sec 11.2. Report a mistake