1
GATE ME 2003
MCQ (Single Correct Answer)
+2
-0.6
In a counter flow heat exchanger, for the hot fluid the heat capacity $$= 2kJ/kg$$ $$K,$$ mass flow rate $$= 5 kg/s,$$ inlet temperature $$ = {150^ \circ }C$$, outlet temperature $$ = {100^ \circ }C$$. For the cold fluid, heat capacity $$= 4 kJ/kg$$ $$K,$$ mass flow rate $$= 10 kg/s,$$ inlet temperature=$$ = {20^ \circ }C$$. Neglecting heat transfer to the surroundings, the outlet temperature of the cold fluid in $$ = {^ \circ }C$$ is
A
$$7.5$$
B
$$32.5$$
C
$$45.5$$
D
$$70.0$$
2
GATE ME 2003
MCQ (Single Correct Answer)
+2
-0.6
Heat is being transferred by convection from water at $${48^ \circ }C$$ to a glass plate whose surface that is exposed to the water is at $${40^0}C.$$ The thermal conductivity of water is $$0.6$$ $$W/mK$$ and the thermal conductivity of glass is $$1.2$$ $$W/mK.$$ The spatial gradient of temp in the water at the water glass interface is
$$dT/dy = 1 \times {10^4}\,\,K/m...$$ GATE ME 2003 Heat Transfer - Conduction Question 31 English

The value of the temperature gradient in the glass at the water-glass interface in $$K/m$$ is

A
$$ - 2 \times {10^4}$$
B
$$0.00$$
C
$$0.5 \times {10^4}$$
D
$$2 \times {10^4}$$
3
GATE ME 2003
MCQ (Single Correct Answer)
+2
-0.6
Consider a laminar boundary layer over a heated flat plate. The free stream velocity is $${U_\infty }.$$ At some distance $$x$$ from the leading edge the velocity boundary layer thickness is $${\delta _v}$$ and the thermal boundary layer is $${\delta _r}.$$ If the Prandtl number is greater than $$1,$$ then
A
$${\delta _v} > {\delta _r}$$
B
$${\delta _r} > {\delta _v}$$
C
$${\delta _v} = {\delta _r} \sim \left( {{U_\infty }} \right)$$
D
$${\delta _v} = {\delta _r} \sim {x^{ - 1/2}}$$
4
GATE ME 2003
MCQ (Single Correct Answer)
+2
-0.6
Heat is being transferred by convection from water at $${48^ \circ }C$$ to a glass plate whose surface that is exposed to the water is at $${40^0}C.$$ The thermal conductivity of water is $$0.6$$ $$W/mK$$ and the thermal conductivity of glass is $$1.2$$ $$W/mK.$$ The spatial gradient of temp in the water at the water glass interface is
$$dT/dy = 1 \times {10^4}\,\,K/m.$$ GATE ME 2003 Heat Transfer - Conduction Question 30 English

The heat transfer coefficient $$h$$ in $$W/{m^2}K$$ is

A
$$0.0$$
B
$$4.8$$
C
$$6$$
D
$$750$$