select the correct answer

$-$ The ability of a material to conduct thermal energy is called:

A$.$ thermal conductivity

B$.$ thermal diffusivity

C$.$ heat transfer coefficient

D$.$ none of the above

$2-$ For a flat plate in a parallel flow, the velocity of the fluid at the boundary layer edge is equal :

A$.0\mathrm{.}5$ of the free stream velocity

B$.0\mathrm{.}99$ of the free stream velocity

C$.$ zero

D$.$ none of the above

$3-$ Outside the boundary layer, the fluid temperature is:

A$.$ dependent on the horizontal distance from the leading edge of the plate

B$.$ dependent on the vertical distance from the plate

C$.$ constant

D$.$ none of the above

$4-$ To calculate the amount of heat transfer rate through a plane wall using the thermal circuit:

A$.$ only temperatures must be known

B$.$ only thermal resistances must be known

C$.$ temperatures and thermal resistances must be known

D$.$ none of the above

$5-$ In convection heat transfer, thermal resistance can be increased by:

A$.$ increasing the convective heat transfer coefficient

B$.$ decreasing the convective heat transfer coefficient

C$.$ increasing the surface area

D$.$ none of the above

$6-$ The conduction heat transfer is inversely proportional to:

A$.$ temperature difference

B$.$ area

C$.$ thermal conductivity

D$.$ none of the above

$7-$ For flow over a flat plate, if Re $>$ Ree, then the flow is:

A$.$ laminar

B$.$ in transition

C$.$

turbulent

D$.$ none of the above

$8-$ Velocity gradients and temperature gradients occur:

A$.$ outside the boundary layer

B$.$ inside the boundary layer

C$.$ at the edge of the boundary layer

D$.$ none of the above