The process of emission of electrons from hot metal surface is called
A. Secondary emission
B. Field emission
C. Thermionic emission
D. Photoelectric emission
Answer: Option C
Solution (By JKSSB Mock Tests)
Thermionic emission: electrons emitted when metal heated to high temperature (e.g., filament in cathode ray tube). Photoelectric: light incident. Field emission: strong electric field. Secondary: bombardment by particles.
Explanation:
An ammeter must have very low resistance so it does not alter the circuit current it is measuring. To convert a sensitive galvanometer into an ammeter, a very low resistance called a 'shunt' is connected in parallel to it. This diverts most of the current away from the delicate galvanometer coil while still allowing a proportional measurement.
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