The coefficient of thermal conductivity of copper is nine times that of steel. In the composite cylindrical bar shown in the figure,what will be the temperature at the junction of copper and steel in $^oC$?

Mortar is a mixture of which of the following?

$A$ hollow pipe of length $0.8 \ m$ is closed at one end. At its open end,a $0.5 \ m$ long uniform string is vibrating in its second harmonic and it resonates with the fundamental frequency of the pipe. If the tension in the wire is $50 \ N$ and the speed of sound is $320 \ ms^{-1}$,the mass of the string is: (in $g$)

$A$ particle of mass $M$ is moving in a horizontal circle of radius $R$ with uniform speed $v$. When it moves from one point to a diametrically opposite point,its

Importance of day length in flowering of plants was first shown in

$x = \frac{1-\sqrt{y}}{1+\sqrt{y}} \Rightarrow \frac{dy}{dx}$ is equal to