Student Login

Home›Chapters›Wave Motion PYQs›Beats›Question 68

NEET 2009 (AIPMT) · Beats

Beats question from NEET 2009 (AIPMT)

Q68NEET 2009 · AIPMTMedium

Beats

Each of the two strings of length 51.6 cm and 49.1 cm are tensioned separately by 20 N force. Mass per unit length of both the strings is same and equal to 1 g/m. When both the strings vibrate simultaneously the number of beats is

Show answer and solution

Answer: (a)

$v = \sqrt{T/\mu} = \sqrt{20/10^{-3}} = 141.4\text{ m/s}$
$f = \dfrac{v}{2L}$ : $f_1 = \dfrac{141.4}{2 \times 0.491} \approx 144.0\text{ Hz}$ , $f_2 = \dfrac{141.4}{2 \times 0.516} \approx 137.0\text{ Hz}$
Beats $= 144.0 - 137.0 \approx 7$
So the answer is (a) 7.

Report a mistake

More questions on Beats

Two sound waves with wavelengths 5.0 m and 5.5. m respectively, each propagate in a gas…NEET 2006 (AIPMT)
Two vibrating tuning forks produce progressive waves given by y₁ = 4sin 500π t and y₂ =…NEET 2005 (AIPMT)
When two tuning forks (fork 1 and fork 2) are sounded simultaneously, 4 beats per second…JEE Main 2005 (AIEEE)
A tuning fork of known frequency 256 Hz makes 5 beats per second with the vibrating…JEE Main 2003 (AIEEE)
A tuning fork arrangement (pair) produces 4 beats/sec with one fork of frequency 288 cps…JEE Main 2002 (AIEEE)
When temperature increases, the frequency of a tuning forkJEE Main 2002 (AIEEE)
Two waves of wavelength 50 cm and 51 cm produce 12 beats/s. The speed of sound isNEET 1999 (AIPMT)
A source of sound gives 5 beats per second, when sounded with another source of frequency…NEET 1995 (AIPMT)