JEE Main 2023 · 31 January · evening · Single correct · +4 / −1
Given below are two statements :
Statement I: In a typical transistor, all three regions emitter, base and collector have same doping level.
Statement II: In a transistor, collector is the thickest and base is the thinnest segment.
In the light of the above statements, choose the most appropriate answer from the options given below.
- (a) Statement I is correct but Statement II is incorrect
- (b) Both Statement I and Statement II are incorrect
- (c) Statement I is incorrect but Statement II is correct
- (d) Both Statement I and Statement II are correct
Answer and solution
Answer (c) Statement I is incorrect but Statement II is correct
Solution
Physics sir · 3 steps
Each region of a transistor has its own job, so each gets its own doping and its own thickness.
- Statement I. The doping levels are different on purpose. The emitter is heavily doped so it can inject many charge carriers. The base is lightly doped and the collector is moderately doped. So Statement I is incorrect.
- Statement II. The base is the thinnest region, so most carriers from the emitter pass straight through it without recombining. The collector is the thickest, because it collects those carriers and gets rid of the heat they produce. So Statement II is correct.
Region Doping Size Why Emitter heavy moderate supplies a large number of carriers Base light thinnest lets carriers cross with little recombination Collector moderate thickest collects carriers and gets rid of the heat - So. Statement I is incorrect and Statement II is correct, which is option (c).
The idea to keep. Emitter: heavily doped. Base: lightly doped and thinnest. Collector: moderately doped and thickest. Link each one to its job and you will not mix them up.
Answer from the NTA final answer key. Solution by PrepWiser.