CUET · PHYSICS · PYQ PAPER 2025

An electron is accelerated through a potential difference of \( V = 36 \text{ V} \). The de-Broglie wavelength associated with it will be

A \( 2.05 \times 10^{-10} \text{ m} \)
B \( 2.26 \times 10^{-9} \text{ m} \)
C \( 1.26 \times 10^{-10} \text{ m} \)
D \( 2 \times 10^{-7} \text{ m} \)

Verified Solution

Answer & Solution

Correct Answer

(A) \( 2.05 \times 10^{-10} \text{ m} \)

Step-by-step Solution

Detailed explanation

\( \lambda = \frac{h}{\sqrt{2me V}} \) \( \lambda = \frac{6.626 \times 10^{-34} \text{ J s}}{\sqrt{2 \times 9.109 \times 10^{-31} \text{ kg} \times 1.602 \times 10^{-19} \text{ C} \times 36 \text{ V}}} \) \( \lambda = 2.05 \times 10^{-10} \text{ m} \)

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 (Quantity)	List-II (Variation with distance)
(A) Electric field due to a point charge	(I) Inversely proportional to the cube of the distance
(B) Electric potential due to a point charge	(II) Inversely proportional to the square of the distance
(C) Electric field due to uniformly charged infinite plane sheet	(III) Inversely proportional to the distance
D) Electric field due to an electric dipole	(IV) Independent of the distance

Choose the correct answer from the options given below:

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LIST I (Phenomenon)	LIST II (Scientists)
A.Dispersion of white light	I.Cassegrain
B.Reflecting type telescope	II.Huygens
C.Double slit experiment	III.Newton
D.Wavefront	IV.Thomas Young