A venturimeter of $$20$$ $$mm$$ throat diameter is used to measure the velocity of water in a horizontal pipe of $$40$$ $$mm$$ diameter. If the pressure difference between the pipe and throat sections is found to be $$30$$ $$kPa$$ then, neglecting frictional losses, the flow velocity is

A $$U$$-tube manometer with a small quantity of mercury is used to measure the static pressure difference between two locations $$A$$ and $$B$$ in a conical section through which an incompressible fluid flows. At a particular flow rate, the mercury column appears as shown in the figure. The density of mercury is $$13600$$ $$kg/{m^3}$$ and $$g = 9.81$$ $$m/{s^2}.$$ Which of the following is correct?

In case of one dimensional heat conduction in a medium with constant properties, $$T$$ is the temperature at position $$x,$$ at time $$t.$$ Then $${{\partial T} \over {\partial t}}$$ is proportional to

Heat flows through a composite slab, as shown below. The depth of the slab is $$1$$ $$m.$$ the $$k$$ values are in $$W/m. K.$$ The overall thermal resistance in $$K/W$$ is