149331 The walls of a closed cubical box of edge $60 \mathrm{~cm}$ are made of material of thickness $1 \mathrm{~mm}$ and thermal conductivity, $4 \times 10^{-4} \mathrm{cal} \mathrm{s}^{-1} \mathrm{~cm}^{-1}{ }^{\circ} \mathrm{C}^{-1}$. The interior of the box is maintained $1000^{\circ} \mathrm{C}$ above the outside temperature by a heater placed inside the box and connected across 400 $\mathrm{V}$ DC supply. The resistance of the heater is

149332 A window used to thermally insulate a room from outside consists of two parallel glass sheets each of area $2.6 \mathrm{~m}^{2}$ and thickness $1 \mathrm{~cm}$ separated by $5 \mathrm{~cm}$ thick stagnant air. In the steady state, the room glass interface is at $18^{\circ} \mathrm{C}$ and the glass-outdoor interface is at $-2{ }^{\circ} \mathrm{C}$. If the thermal conductivities of glass and air are respectively $0.8 \mathrm{Wm}^{-1} \mathrm{~K}^{-1}$ and $0.08 \mathrm{Wm}^{-1} \mathrm{~K}^{-1}$, the rate of flow of heat through the window is

149333 A heat flux of $4000 \mathrm{~J} / \mathrm{s}$ is to be passed through a copper rod of length $10 \mathrm{~cm}$ and area of crosssection $100 \mathrm{sq} . \mathrm{cm}$. The thermal conductivity of copper is $400 \mathrm{~W} / \mathrm{m}^{\circ} \mathrm{C}$. The two ends of this rod must be kept at a temperature difference of

149334 A body of length $1 \mathrm{~m}$ having cross-sectional area $0.75 \mathrm{~m}^{2}$ has heat flow through it at the rate of $6000 \mathrm{Joule} / \mathrm{sec}$. Then find the temperature difference if $K=200 \mathrm{Jm}^{-1} K^{-1}$.

149336 Figure shows a copper rod joined to a steel rod. The rods have equal length and equal cross-sectional area. The free end of the copper rod is kept at $0^{\circ} \mathrm{C}$ and that of steel rod is kept at $100^{\circ} \mathrm{C}$. Find the temperature of the junction of the rod. Conductivity of copper $=390$ $\mathrm{W} / \mathrm{m}^{\circ} \mathrm{C}$. Conductivity of steel $=46 \mathrm{~W} / \mathrm{m}^{\circ} \mathrm{C}$
$0^{\circ} \mathrm{C} \text { Copper } \quad \text { Steel } 100^{\circ} \mathrm{C}$

149331 The walls of a closed cubical box of edge $60 \mathrm{~cm}$ are made of material of thickness $1 \mathrm{~mm}$ and thermal conductivity, $4 \times 10^{-4} \mathrm{cal} \mathrm{s}^{-1} \mathrm{~cm}^{-1}{ }^{\circ} \mathrm{C}^{-1}$. The interior of the box is maintained $1000^{\circ} \mathrm{C}$ above the outside temperature by a heater placed inside the box and connected across 400 $\mathrm{V}$ DC supply. The resistance of the heater is

149332 A window used to thermally insulate a room from outside consists of two parallel glass sheets each of area $2.6 \mathrm{~m}^{2}$ and thickness $1 \mathrm{~cm}$ separated by $5 \mathrm{~cm}$ thick stagnant air. In the steady state, the room glass interface is at $18^{\circ} \mathrm{C}$ and the glass-outdoor interface is at $-2{ }^{\circ} \mathrm{C}$. If the thermal conductivities of glass and air are respectively $0.8 \mathrm{Wm}^{-1} \mathrm{~K}^{-1}$ and $0.08 \mathrm{Wm}^{-1} \mathrm{~K}^{-1}$, the rate of flow of heat through the window is

149333 A heat flux of $4000 \mathrm{~J} / \mathrm{s}$ is to be passed through a copper rod of length $10 \mathrm{~cm}$ and area of crosssection $100 \mathrm{sq} . \mathrm{cm}$. The thermal conductivity of copper is $400 \mathrm{~W} / \mathrm{m}^{\circ} \mathrm{C}$. The two ends of this rod must be kept at a temperature difference of

149334 A body of length $1 \mathrm{~m}$ having cross-sectional area $0.75 \mathrm{~m}^{2}$ has heat flow through it at the rate of $6000 \mathrm{Joule} / \mathrm{sec}$. Then find the temperature difference if $K=200 \mathrm{Jm}^{-1} K^{-1}$.

149336 Figure shows a copper rod joined to a steel rod. The rods have equal length and equal cross-sectional area. The free end of the copper rod is kept at $0^{\circ} \mathrm{C}$ and that of steel rod is kept at $100^{\circ} \mathrm{C}$. Find the temperature of the junction of the rod. Conductivity of copper $=390$ $\mathrm{W} / \mathrm{m}^{\circ} \mathrm{C}$. Conductivity of steel $=46 \mathrm{~W} / \mathrm{m}^{\circ} \mathrm{C}$
$0^{\circ} \mathrm{C} \text { Copper } \quad \text { Steel } 100^{\circ} \mathrm{C}$

149331 The walls of a closed cubical box of edge $60 \mathrm{~cm}$ are made of material of thickness $1 \mathrm{~mm}$ and thermal conductivity, $4 \times 10^{-4} \mathrm{cal} \mathrm{s}^{-1} \mathrm{~cm}^{-1}{ }^{\circ} \mathrm{C}^{-1}$. The interior of the box is maintained $1000^{\circ} \mathrm{C}$ above the outside temperature by a heater placed inside the box and connected across 400 $\mathrm{V}$ DC supply. The resistance of the heater is

149332 A window used to thermally insulate a room from outside consists of two parallel glass sheets each of area $2.6 \mathrm{~m}^{2}$ and thickness $1 \mathrm{~cm}$ separated by $5 \mathrm{~cm}$ thick stagnant air. In the steady state, the room glass interface is at $18^{\circ} \mathrm{C}$ and the glass-outdoor interface is at $-2{ }^{\circ} \mathrm{C}$. If the thermal conductivities of glass and air are respectively $0.8 \mathrm{Wm}^{-1} \mathrm{~K}^{-1}$ and $0.08 \mathrm{Wm}^{-1} \mathrm{~K}^{-1}$, the rate of flow of heat through the window is

149333 A heat flux of $4000 \mathrm{~J} / \mathrm{s}$ is to be passed through a copper rod of length $10 \mathrm{~cm}$ and area of crosssection $100 \mathrm{sq} . \mathrm{cm}$. The thermal conductivity of copper is $400 \mathrm{~W} / \mathrm{m}^{\circ} \mathrm{C}$. The two ends of this rod must be kept at a temperature difference of

149334 A body of length $1 \mathrm{~m}$ having cross-sectional area $0.75 \mathrm{~m}^{2}$ has heat flow through it at the rate of $6000 \mathrm{Joule} / \mathrm{sec}$. Then find the temperature difference if $K=200 \mathrm{Jm}^{-1} K^{-1}$.

149336 Figure shows a copper rod joined to a steel rod. The rods have equal length and equal cross-sectional area. The free end of the copper rod is kept at $0^{\circ} \mathrm{C}$ and that of steel rod is kept at $100^{\circ} \mathrm{C}$. Find the temperature of the junction of the rod. Conductivity of copper $=390$ $\mathrm{W} / \mathrm{m}^{\circ} \mathrm{C}$. Conductivity of steel $=46 \mathrm{~W} / \mathrm{m}^{\circ} \mathrm{C}$
$0^{\circ} \mathrm{C} \text { Copper } \quad \text { Steel } 100^{\circ} \mathrm{C}$

149331 The walls of a closed cubical box of edge $60 \mathrm{~cm}$ are made of material of thickness $1 \mathrm{~mm}$ and thermal conductivity, $4 \times 10^{-4} \mathrm{cal} \mathrm{s}^{-1} \mathrm{~cm}^{-1}{ }^{\circ} \mathrm{C}^{-1}$. The interior of the box is maintained $1000^{\circ} \mathrm{C}$ above the outside temperature by a heater placed inside the box and connected across 400 $\mathrm{V}$ DC supply. The resistance of the heater is

149332 A window used to thermally insulate a room from outside consists of two parallel glass sheets each of area $2.6 \mathrm{~m}^{2}$ and thickness $1 \mathrm{~cm}$ separated by $5 \mathrm{~cm}$ thick stagnant air. In the steady state, the room glass interface is at $18^{\circ} \mathrm{C}$ and the glass-outdoor interface is at $-2{ }^{\circ} \mathrm{C}$. If the thermal conductivities of glass and air are respectively $0.8 \mathrm{Wm}^{-1} \mathrm{~K}^{-1}$ and $0.08 \mathrm{Wm}^{-1} \mathrm{~K}^{-1}$, the rate of flow of heat through the window is

149333 A heat flux of $4000 \mathrm{~J} / \mathrm{s}$ is to be passed through a copper rod of length $10 \mathrm{~cm}$ and area of crosssection $100 \mathrm{sq} . \mathrm{cm}$. The thermal conductivity of copper is $400 \mathrm{~W} / \mathrm{m}^{\circ} \mathrm{C}$. The two ends of this rod must be kept at a temperature difference of

149334 A body of length $1 \mathrm{~m}$ having cross-sectional area $0.75 \mathrm{~m}^{2}$ has heat flow through it at the rate of $6000 \mathrm{Joule} / \mathrm{sec}$. Then find the temperature difference if $K=200 \mathrm{Jm}^{-1} K^{-1}$.

149336 Figure shows a copper rod joined to a steel rod. The rods have equal length and equal cross-sectional area. The free end of the copper rod is kept at $0^{\circ} \mathrm{C}$ and that of steel rod is kept at $100^{\circ} \mathrm{C}$. Find the temperature of the junction of the rod. Conductivity of copper $=390$ $\mathrm{W} / \mathrm{m}^{\circ} \mathrm{C}$. Conductivity of steel $=46 \mathrm{~W} / \mathrm{m}^{\circ} \mathrm{C}$
$0^{\circ} \mathrm{C} \text { Copper } \quad \text { Steel } 100^{\circ} \mathrm{C}$

149331 The walls of a closed cubical box of edge $60 \mathrm{~cm}$ are made of material of thickness $1 \mathrm{~mm}$ and thermal conductivity, $4 \times 10^{-4} \mathrm{cal} \mathrm{s}^{-1} \mathrm{~cm}^{-1}{ }^{\circ} \mathrm{C}^{-1}$. The interior of the box is maintained $1000^{\circ} \mathrm{C}$ above the outside temperature by a heater placed inside the box and connected across 400 $\mathrm{V}$ DC supply. The resistance of the heater is

149332 A window used to thermally insulate a room from outside consists of two parallel glass sheets each of area $2.6 \mathrm{~m}^{2}$ and thickness $1 \mathrm{~cm}$ separated by $5 \mathrm{~cm}$ thick stagnant air. In the steady state, the room glass interface is at $18^{\circ} \mathrm{C}$ and the glass-outdoor interface is at $-2{ }^{\circ} \mathrm{C}$. If the thermal conductivities of glass and air are respectively $0.8 \mathrm{Wm}^{-1} \mathrm{~K}^{-1}$ and $0.08 \mathrm{Wm}^{-1} \mathrm{~K}^{-1}$, the rate of flow of heat through the window is

149333 A heat flux of $4000 \mathrm{~J} / \mathrm{s}$ is to be passed through a copper rod of length $10 \mathrm{~cm}$ and area of crosssection $100 \mathrm{sq} . \mathrm{cm}$. The thermal conductivity of copper is $400 \mathrm{~W} / \mathrm{m}^{\circ} \mathrm{C}$. The two ends of this rod must be kept at a temperature difference of

149334 A body of length $1 \mathrm{~m}$ having cross-sectional area $0.75 \mathrm{~m}^{2}$ has heat flow through it at the rate of $6000 \mathrm{Joule} / \mathrm{sec}$. Then find the temperature difference if $K=200 \mathrm{Jm}^{-1} K^{-1}$.

149336 Figure shows a copper rod joined to a steel rod. The rods have equal length and equal cross-sectional area. The free end of the copper rod is kept at $0^{\circ} \mathrm{C}$ and that of steel rod is kept at $100^{\circ} \mathrm{C}$. Find the temperature of the junction of the rod. Conductivity of copper $=390$ $\mathrm{W} / \mathrm{m}^{\circ} \mathrm{C}$. Conductivity of steel $=46 \mathrm{~W} / \mathrm{m}^{\circ} \mathrm{C}$
$0^{\circ} \mathrm{C} \text { Copper } \quad \text { Steel } 100^{\circ} \mathrm{C}$