$1$ Thermal entre correct statement.

$1$ I Thermat entry leneth $(L_4)$ is alwave more than hydrodyamic entry leneth $($Ca$)$

I I Fully developed flow is alwavs fess than hudrodynamic entry length.

$1$ Entry lengths are xero exbts for distances $>L$ when $P_r=1.$

$(3)$ Identify the correct form of $Ne$

$($ I $q=h(r,-r)$ for of Newtor's Law of Cooling

$(1)q=h(r_x{r}_0)$ for film condensation.

i $1,9=h(T_i-T_{-})$for internal pipe flow.

I $1,q^{}=h(r_{n+r}-r_i)$ for flow over a cylinder.

$(4)$ Overall Heat for film condensation.

I I $\frac{1}{u}=\frac{1}{h},+\frac{1}{h_0}$ applient. Select the correct option.

I I $\frac{1}{U}=\frac{1}{h},+\frac{1}{h_0}$ applies for a thin smooth metal wall between the fluid streams.

$1A,U_s=A_{,}{U}_j.$ applies for a thin finned metal wall between the fluid streams.

$(5)$ The laminar hydrodynamic and thermal boundary layers on a flat plate have same thickness

when the Prandtl number of the flowing fluid is: $($select the correct statement$).$

i I Close to zero.

l$.$ small.

I $]$ Approximately one.

$[1$ Large.

Question # $1($b$)$

$(6)$ useints each$)$ Select one false answer by putting in the appropriate box:

I $]$ Baffles are used inside the tubes to exhangers. Select the false statement.

$[]$ Baffles are used to promote cross to enhance turbulence.

$[]$ A larger number of baffles incross$-$flow on the shell$-$side.

I I Baffles enhance heat transfereases pressure drop on the shell$-$side.

l $]$ Use of the morigns. Select the false statement.

$[]$ The LMTD metho viscous fluid is better suited for the shell side.

I I Use of the fluid with mor only be used for calculating the heat exchanger area.

$[]$ Toxic fluids are not suitare fouling is better suited for the tube side.