JEE Main 2021 · PhysicsMultiple choiceSingle correctEasyConceptual

JEE Main 27 August 2021, Shift 2, Physics Q17

Question 17 of 90 in this shift, Physics question 17 of 30, Section A.

For a transistor

\alpha

and

\beta

are given as

\alpha=\frac{I_C}{I_E}

and

\beta=\frac{I_C}{I_B}

. Then the correct relation between

\alpha

and

\beta

will be :

(1) $\alpha=\frac{\beta}{1-\beta}$
(2) $\alpha\beta=1$
(3) $\beta=\frac{\alpha}{1-\alpha}$ Official answer
(4) $\alpha=\frac{1-\beta}{\beta}$

Official answer

Option 3

NTA final key.

Chapter: Semiconductor Electronics: Materials, Devices and Simple Circuits
Topic: Transistors
Idea tested: Current Gains Alpha and Beta

Same idea in other shifts

Asked 4× in all

12 Apr 2023, Shift 1 · Q49In an n-p-n common emitter (CE) transistor the collector current changes from 5 mA to 16 mA for the change in base current from 100 $\mu$ A…EasySingle correct
24 Feb 2021, Shift 1 · Q16If an emitter current is changed by 4 mA, the collector current changes by 3.5 mA. The value of $\beta$ will be :EasySingle correct
18 Mar 2021, Shift 2 · Q15The correct relation between $\alpha$ (ratio of collector current to emitter current) and $\beta$ (ratio of collector current to base…EasySingle correct

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.