A composite flat wall of a furnace is made of two materials 'A' and 'B'. The thermal conductivity of 'A' is twice of that of material 'B', while the thickness of layer of 'A' is half that of B. If the temperature at the two sides of the wall are 400 and 1200°K, then the temperature drop (in °K) across the layer of material 'A' is

Heat Transfer
A composite flat wall of a furnace is made of two materials 'A' and 'B'. The thermal conductivity of 'A' is twice of that of material 'B', while the thickness of layer of 'A' is half that of B. If the temperature at the two sides of the wall are 400 and 1200°K, then the temperature drop (in °K) across the layer of material 'A' is

150

125

160

133

150

125

160

133

ANSWER DOWNLOAD EXAMIANS APP

Heat Transfer
For an ideal black body

Reflectivity = 1

Emissivity = 0

Absorptivity = 1

Transmissivity = 1

Reflectivity = 1

Emissivity = 0

Absorptivity = 1

Transmissivity = 1

ANSWER DOWNLOAD EXAMIANS APP

Heat Transfer
A steel sphere of radius 0.1 m at 400°K is immersed in an oil at 300°K. If the centre of the sphere reaches 350°K in 20 minutes, how long will it take for a 0.05 m radius steel sphere to reach the same temperature (at the centre) under identical conditions ? Assume that the conductive heat transfer co-efficient is infinitely large.

10 minutes

20 minutes

40 minutes

5 minutes

10 minutes

20 minutes

40 minutes

5 minutes

ANSWER DOWNLOAD EXAMIANS APP

Heat Transfer
The absorptivity of a body is equal to its emissivity

for circular bodies

none of the listed here

under thermal equilibrium

at a particular temperature

for circular bodies

none of the listed here

under thermal equilibrium

at a particular temperature

ANSWER DOWNLOAD EXAMIANS APP

Heat Transfer
In regenerative air preheater (as practised in heating of coke ovens), the heat is transferred

Through a metallic wall

None of these

By direct contact of hot flue gas with air

By heating an intermediate material (like chequor bricks) and then heating the air from this hot material

Through a metallic wall

None of these

By direct contact of hot flue gas with air

By heating an intermediate material (like chequor bricks) and then heating the air from this hot material

ANSWER DOWNLOAD EXAMIANS APP

Heat Transfer
In a single evaporator system, the steam economy __________ by creating vacuum in the evaporator.

May increase or decrease, depends on the vacuum

Decreases

Increases

Remains constant

May increase or decrease, depends on the vacuum

Decreases

Increases

Remains constant

ANSWER DOWNLOAD EXAMIANS APP

Heat Transfer

Heat Transfer For an ideal black body

Heat Transfer The absorptivity of a body is equal to its emissivity

Heat Transfer In regenerative air preheater (as practised in heating of coke ovens), the heat is transferred

Heat Transfer In a single evaporator system, the steam economy __________ by creating vacuum in the evaporator.

Heat Transfer
For an ideal black body

Heat Transfer
The absorptivity of a body is equal to its emissivity

Heat Transfer
In regenerative air preheater (as practised in heating of coke ovens), the heat is transferred

Heat Transfer
In a single evaporator system, the steam economy __________ by creating vacuum in the evaporator.