NEET · Physics · STD 11 - 14. waves and sound

The length of the string of a musical instrument is \(90 \;cm\) and has a fundamental frequency of \(120 \;Hz\). Where (In \(cm\)) should it be pressed to produce fundamental frequency of \(180 \;Hz ?\)

A \(80\)
B \(75\)
C \(60\)
D \(45\)

Verified Solution

Answer & Solution

Correct Answer

(C) \(60\)

Step-by-step Solution

Detailed explanation

Frequency of stretched string \(n =\frac{1}{2 \ell} \sqrt{\frac{ T }{ m }}\)

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 \(I\) (Spectral Lines of Hydrogen for transitions from)	List \(II\) (Wavelengths (\(nm\)))
\(A\) \(n_2=3 \text { to } n_1=2\)	\(I\) \(410.2\)
\(B\) \(n_2=4 \text { to } n_1=2\)	\(II\) \(434.1\)
\(C\) \(n_2=5 \text { to } n_1=2\)	\(III\) \(656.3\)
\(D\) \(n_2=6 \text { to } n_1=2\)	\(IV\) \(486.1\)

Choose the correct answer from the options given below:

NEET 2024 Medium

Explore more questions on app

From NEET

Explore more questions on app

	List - I		List - II
A.	Chlorophyll a	(i)	Yellow-green
B.	Chlorophyll b	(ii)	Yellow
C.	Xanthophylls	(iii)	Blue-green
D.	Carotenoids	(iv)	Yellow to Yellow-orange