CUET · PHYSICS · PYQ PAPER 2023

The correct relation between the transistor parameters \(\alpha\) and \(\beta\) is -

A \(\beta=\frac{1-\alpha}{\alpha}\)
B \(\beta=\frac{\alpha}{1-\alpha}\)
C \(\beta=\frac{1+\alpha}{\alpha}\)
D \(\beta=\frac{\alpha}{1+\alpha}\)

Verified Solution

Answer & Solution

Correct Answer

(B) \(\beta=\frac{\alpha}{1-\alpha}\)

Step-by-step Solution

Detailed explanation

Since \(I_E=I_B+I_C\), we can relate the current gains by the equation \(\frac{1}{\alpha}=\frac{1}{\beta}+1\). Solving this for \(\beta\) gives the relation \(\beta=\frac{\alpha}{1-\alpha}\), showing that as \(\alpha\) approaches 1 , the value of \(\beta\) becomes very large. B)…

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.

Same subject

Match List-I with List-II

List-I (Phenomenon)	List-II (Characteristics)
(A) Reflection	(I) Used for reducing glare
(B) Refraction	(II) Change in path when a light is incident on opaque medium
(C) Interference	(III) Change in path when a light is incident on transparent medium
(D) Polarisation	(IV) Light added to light to produce darkness

Choose the correct answer from the options given below:

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