Get Answers to all your Questions

header-bg qa

A uniform thin rope of length 12\; m and mass 6\; kg has vertically support and a block of mass 2\; kg is attached to its free end. A transverse short wave train of wavelength 6cm is produced at the lower end of the rope. What is the wavelength of the wave train (in cm) when it reaches top of the rope
   
Option: 1 3
Option: 2 6
Option: 3 12  
Option: 4 9

Answers (1)

best_answer

\mu =\frac{6}{12}=0.5

using V=\frac{T}{\mu}

At a distance x from the bottom 

V=\sqrt{\frac{T}{\mu}}= \sqrt{\frac{(2g+\mu xg)}{\mu}}=\sqrt{\frac{20+5x}{0.5}}

at x=0, V_1=\sqrt{\frac{T}{\mu}}=\sqrt{\frac{20}{0.5}}=\sqrt{40}

and \lambda _1=6 \ cm

f=\frac{V_1}{\lambda _1}=\frac{\sqrt{40}}{6}

Now at x=12 cm

V_0=\sqrt{\frac{T}{\mu}}= \sqrt{\frac{(2g+\mu xg)}{\mu}}=\sqrt{\frac{20+5x}{0.5}}=\sqrt{\frac{20+(5*12)}{0.5}}=\sqrt{\frac{80}{0.5}}\\ \Rightarrow V_0=2\sqrt{40}

So, \lambda _0=\frac{V_0}{f}=\frac{2\sqrt{40}}{\frac{\sqrt{40}}{6}}=12 cm

 

Posted by

avinash.dongre

View full answer

JEE Main high-scoring chapters and topics

Study 40% syllabus and score up to 100% marks in JEE