The cross-sectional area of one limb of a U-tube manometer [ Figure shown below ] is made $$500$$ time larger than the other, so that the pressure difference between the two limbs can be determined by measuring $$'h'$$ on one limb of the manometer. The percentage error involved is :

A jet of water issues from a Nozzle with a velocity $$20$$ $$m/s$$ and it impinges normally on a flat plate moving away from it at $$10\,m/s.$$ The cross-sectional area of the jet is $$0.01$$ $${m^2},$$ and the density of water $$ =1000\,\,kg/{m^3}.$$ The force developed on the plate is:

In a band operated liquid sprayer (figure shown below) the liquid from the container rises to the top of the tube because of :

A double pipe counter flow heat exchanger is to be designed to cool $$12000$$ $$kg/hr$$ of an oil of specific heat $$1.95$$ $$kJ/kgK$$ from $$\,85{}^ \circ C$$ to $$\,55{}^ \circ C$$ by water entering the heat exchanger at $$\,30{}^ \circ C$$ and leaving at $$\,45{}^ \circ C$$. If the $$OHTC$$ of heat exchanger is $$400$$ $$\,W/{m^2}K.\,$$ Calculate the $$LMTD$$ and the surface area of the heat exchanger