CUET · PHYSICS · PYQ PAPER 2023

If the wave length of 1st line of Balmer series of hydrogen is 6561A, the wavelength of the 2nd line of series will be:

A 9860 Å
B 4419 Å
C 4860 Å
D 8857 Å

Verified Solution

Answer & Solution

Correct Answer

(C) 4860 Å

Step-by-step Solution

Detailed explanation

\( \frac{1}{\lambda_1} = R_H \left( \frac{1}{2^2} - \frac{1}{3^2} \right) = R_H \frac{5}{36} \) \( \frac{1}{\lambda_2} = R_H \left( \frac{1}{2^2} - \frac{1}{4^2} \right) = R_H \frac{3}{16} \) \( \frac{\lambda_2}{\lambda_1} = \frac{5/36}{3/16} = \frac{20}{27} \)…

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	List-II
(A) \( \oint {B} \cdot d{s} = 0 \)	(I) magnetic field lines
(B) Directional property of freely suspended magnet	(II) circulating ions
(C) Never intersect each other	(III) torque on magnetic dipole
(D) Magnetic field of earth	(IV) monopoles in magnetism do not exist

Choose the correct answer from the options given below :

CUET 2023 Hard

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