What will be the change in phase of wave due to reflection from rigid support ?

A string of length $1\,\,m$ and linear mass density $0.01\,\,kgm^{-1}$ is stretched to a tension of $100\,\,N.$ When both ends of the string are fixed, the three lowest frequencies for standing wave are $f_1, f_2$ and $f_3$. When only one end of the string is fixed, the three lowest frequencies for standing wave are $n_1, n_2$ and $n_3$. Then

The transverse displacement of a string (clamped at its both ends) is given by

$y(x,t)\, = \,0.6\,\sin \,\left( {\frac{{2\pi }}{3}x} \right)\,\cos \,(120\,\pi t)$

where $x$ and $y$ are in $metre$ and $t$ in $second$ . The length of the string is $1.5\,m$ and its mass is $3.0\times 10^{-2}\,kg$ the tension in the string will be .... $N$

A string is producing transverse vibration whose equation is $y = 0.021\;\sin (x + 30t)$, Where $x$ and $y$ are in meters and $t$ is in seconds. If the linear density of the string is $1.3 \times {10^{ - 4}}\,kg/m,$ then the tension in the string in $N$ will be

The frequency of a sonometer wire is $100 Hz$. When the weights producing the tensions are completely immersed in water, the frequency becomes $80 Hz$ and on immersing the weights in a certain liquid, the frequency becomes $60 Hz$. The specific gravity of the liquid is 

Length of a string tied to two rigid supports is $40 cm$. Maximum length (wavelength in $cm$) of a stationary wave produced on it is ... $cm$