MyQuestionIcon

1

You visited us 1 times! Enjoying our articles? Unlock Full Access!

Convection

A double-plan...

Question

A double-plane window consist of two glass sheets each of area $1 m^{2}$ and thickness $0.01 m$ separated by a $0.05 m$ thick stagnant air space In the steady state, the room glass interface and the glass outdoor interface are at constant temperature of $27^{o} C$ and $0^{o} C$ respectively. The rate of heat flow through the window plane is (Given , $k_{g l a s s} = 0.8 W m^{- 1} K^{- 1}, K_{a i r} = 0.08 W m^{- 1} K^{- 1})$

A

41.5 W

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses

B

31.5 W

No worries! We‘ve got your back. Try BYJU‘S free classes today!

C

21.5 W

No worries! We‘ve got your back. Try BYJU‘S free classes today!

D

11.5 W

No worries! We‘ve got your back. Try BYJU‘S free classes today!

Open in App

Solution

The correct option is A $41.5 W$
Total thermal resistance is
$R = \frac{t_{1}}{K_{1} A_{1}} + \frac{t_{2}}{K_{2} A_{2}} + \frac{t_{1}}{K_{1} A_{1}}$

$R = 2 \times \frac{0.01}{0.8 \times 1} + \frac{0.05}{0.08 \times 1} = 0.65 W^{- 1} K$

$∴$ Heat current $, H = \frac{△ T}{R} = \frac{27 - 0}{0.65} = 41.5 W$

Suggest Corrections

thumbs-up

0

Similar questions

Q. A double-plane window consists of two glass sheets each of area

1

and thickness 0.01 m separated by a 0.05 m thick stagnant air space. In the steady state, the room glass interface and the glass outdoor interface are at constant temperature of

27

0

respectively. The rate of heat flow through the window pane is (Given,

K_{g l a s s} = 0.8 W m^{- 1} K^{- 1}, K_{a i r} = 0.08 W m^{- 1} K^{- 1}

Q. A double-pane window used for insulating a room thermally from outside consists of two glass sheets each of area 1m

^{2}

and thickness 0.01m separated by 0.05m thick stagnant air space.In the steady state, the room-glass interface and the glass-outdoor interface are at constant temperatures of 270

^{o}

^{o}

C respectively.The thermal conductivity of glass is 0.8 and of air 0.08Wm

^{- 1}

^{- 1}

.

The rate of flow of heat through the window pane is nearly equal to:

Q. A double-pane window used for insulating a room thermally from outside consists of two glass sheets each of area 1m

^{2}

and thickness 0.01m separated by 0.05m thick stagnant air space.In the steady state, the room-glass interface and the glass-outdoor interface are at constanttemperatures of 27

^{o}

^{o}

C respectively.The thermal conductivity of glass is 0.8 and of air 0.08Wm

^{- 1}

^{- 1}

The temperatures of the inner glass-air interface is

Q. A double-pane window used for insulating a room thermally from outside consists of two glass sheets each of area 1m

^{2}

0.01

0.05

m thick stagnant air space.In the steady state, the room-glass interface and the glass-outdoor interface are at constant temperatures of 27

^{o}

^{o}

C respectively.The thermal conductivity of glass is

0.8

and of air 0.08Wm

^{- 1}

^{- 1}

The temperature of the outer glass-air interface is

Q. A room has a window fitted with a single 1.0 m × 2.0 m glass of thickness 2 mm. (a) Calculate the rate of heat flow through the closed window when the temperature inside the room is 32°C and the outside is 40°C. (b) The glass is now replaced by two glasspanes, each having a thickness of 1 mm and separated by a distance of 1 mm. Calculate the rate of heat flow under the same conditions of temperature. Thermal conductivity of window glass = 1.0 J s⁻¹ m⁻¹°C⁻¹ and that of air = 0.025 J s⁻¹ m⁻¹°C⁻¹.

View More

Join BYJU'S Learning Program

similar_icon

Related Videos

lock

Convection

PHYSICS

Watch in App

explore_more_icon

Explore more

Standard XII Physics

Join BYJU'S Learning Program

CrossIcon