00. Conduction
Heat Transfer

149347 Three identical thermal conductors are connected as shown in figure. Considering no heat loss due to radiation, temperature at the junction will be

1 $40^{\circ} \mathrm{C}$
2 $60^{\circ} \mathrm{C}$
3 $50^{\circ} \mathrm{C}$
4 $35^{\circ} \mathrm{C}$
Heat Transfer

149348 Which of the following circular rods. (given radius $r$ and length $l$ ) each made of the same material as whose ends are maintained at the same temperature will conduct most heat?

1 $\mathrm{r}=2 \mathrm{r}_{0} ; l=2 l_{0}$
2 $\mathrm{r}=2 \mathrm{r}_{0} ; l=l_{0}$
3 $\mathrm{r}=\mathrm{r}_{0} ; l=l_{0}$
4 $\mathrm{r}=\mathrm{r}_{0} ; l=2 l_{0}$
Heat Transfer

149350 A composite slab is prepared with two different materials $A$ and $B$. The relation between their coefficient of thermal conductivity and thickness is given as $K_{A}=\frac{K_{B}}{2}$ and $X_{A}=2 X_{B}$, respectively. If the temperature of faces of $A$ and $B$ are $75^{\circ} \mathrm{C}$ and $50^{\circ} \mathrm{C}$ respectively, what will be the temperature of common surface?

1 $75^{\circ} \mathrm{C}$
2 $50^{\circ} \mathrm{C}$
3 $55^{\circ} \mathrm{C}$
4 $125^{\circ} \mathrm{C}$
Heat Transfer

149351 Two thin metallic spherical shells of radii 20 $\mathrm{cm}$ and $30 \mathrm{~cm}$, respectively are placed with their centres coinciding. A material of thermal condutivity $\alpha$ is filled in the space between the shells. The inner shell is maintained at $300 \mathrm{~K}$ and the outer shell at $310 \mathrm{~K}$. If the rate at which heat flows radially through the material is $40 \mathrm{~W}$, find the value of $\alpha$ (in units of $\mathrm{J} \mathrm{s}^{-1} \mathrm{~m}^{-1}$ $\mathrm{K}^{-1}$ ).

1 $\frac{3}{\pi}$
2 $\frac{4 \pi}{3}$
3 $\frac{5}{3 \pi}$
4 $\frac{\pi}{2}$
NEET Test Series from KOTA - 10 Papers In MS WORD WhatsApp Here
Heat Transfer

149347 Three identical thermal conductors are connected as shown in figure. Considering no heat loss due to radiation, temperature at the junction will be

1 $40^{\circ} \mathrm{C}$
2 $60^{\circ} \mathrm{C}$
3 $50^{\circ} \mathrm{C}$
4 $35^{\circ} \mathrm{C}$
Heat Transfer

149348 Which of the following circular rods. (given radius $r$ and length $l$ ) each made of the same material as whose ends are maintained at the same temperature will conduct most heat?

1 $\mathrm{r}=2 \mathrm{r}_{0} ; l=2 l_{0}$
2 $\mathrm{r}=2 \mathrm{r}_{0} ; l=l_{0}$
3 $\mathrm{r}=\mathrm{r}_{0} ; l=l_{0}$
4 $\mathrm{r}=\mathrm{r}_{0} ; l=2 l_{0}$
Heat Transfer

149350 A composite slab is prepared with two different materials $A$ and $B$. The relation between their coefficient of thermal conductivity and thickness is given as $K_{A}=\frac{K_{B}}{2}$ and $X_{A}=2 X_{B}$, respectively. If the temperature of faces of $A$ and $B$ are $75^{\circ} \mathrm{C}$ and $50^{\circ} \mathrm{C}$ respectively, what will be the temperature of common surface?

1 $75^{\circ} \mathrm{C}$
2 $50^{\circ} \mathrm{C}$
3 $55^{\circ} \mathrm{C}$
4 $125^{\circ} \mathrm{C}$
Heat Transfer

149351 Two thin metallic spherical shells of radii 20 $\mathrm{cm}$ and $30 \mathrm{~cm}$, respectively are placed with their centres coinciding. A material of thermal condutivity $\alpha$ is filled in the space between the shells. The inner shell is maintained at $300 \mathrm{~K}$ and the outer shell at $310 \mathrm{~K}$. If the rate at which heat flows radially through the material is $40 \mathrm{~W}$, find the value of $\alpha$ (in units of $\mathrm{J} \mathrm{s}^{-1} \mathrm{~m}^{-1}$ $\mathrm{K}^{-1}$ ).

1 $\frac{3}{\pi}$
2 $\frac{4 \pi}{3}$
3 $\frac{5}{3 \pi}$
4 $\frac{\pi}{2}$
Heat Transfer

149347 Three identical thermal conductors are connected as shown in figure. Considering no heat loss due to radiation, temperature at the junction will be

1 $40^{\circ} \mathrm{C}$
2 $60^{\circ} \mathrm{C}$
3 $50^{\circ} \mathrm{C}$
4 $35^{\circ} \mathrm{C}$
Heat Transfer

149348 Which of the following circular rods. (given radius $r$ and length $l$ ) each made of the same material as whose ends are maintained at the same temperature will conduct most heat?

1 $\mathrm{r}=2 \mathrm{r}_{0} ; l=2 l_{0}$
2 $\mathrm{r}=2 \mathrm{r}_{0} ; l=l_{0}$
3 $\mathrm{r}=\mathrm{r}_{0} ; l=l_{0}$
4 $\mathrm{r}=\mathrm{r}_{0} ; l=2 l_{0}$
Heat Transfer

149350 A composite slab is prepared with two different materials $A$ and $B$. The relation between their coefficient of thermal conductivity and thickness is given as $K_{A}=\frac{K_{B}}{2}$ and $X_{A}=2 X_{B}$, respectively. If the temperature of faces of $A$ and $B$ are $75^{\circ} \mathrm{C}$ and $50^{\circ} \mathrm{C}$ respectively, what will be the temperature of common surface?

1 $75^{\circ} \mathrm{C}$
2 $50^{\circ} \mathrm{C}$
3 $55^{\circ} \mathrm{C}$
4 $125^{\circ} \mathrm{C}$
Heat Transfer

149351 Two thin metallic spherical shells of radii 20 $\mathrm{cm}$ and $30 \mathrm{~cm}$, respectively are placed with their centres coinciding. A material of thermal condutivity $\alpha$ is filled in the space between the shells. The inner shell is maintained at $300 \mathrm{~K}$ and the outer shell at $310 \mathrm{~K}$. If the rate at which heat flows radially through the material is $40 \mathrm{~W}$, find the value of $\alpha$ (in units of $\mathrm{J} \mathrm{s}^{-1} \mathrm{~m}^{-1}$ $\mathrm{K}^{-1}$ ).

1 $\frac{3}{\pi}$
2 $\frac{4 \pi}{3}$
3 $\frac{5}{3 \pi}$
4 $\frac{\pi}{2}$
Heat Transfer

149347 Three identical thermal conductors are connected as shown in figure. Considering no heat loss due to radiation, temperature at the junction will be

1 $40^{\circ} \mathrm{C}$
2 $60^{\circ} \mathrm{C}$
3 $50^{\circ} \mathrm{C}$
4 $35^{\circ} \mathrm{C}$
Heat Transfer

149348 Which of the following circular rods. (given radius $r$ and length $l$ ) each made of the same material as whose ends are maintained at the same temperature will conduct most heat?

1 $\mathrm{r}=2 \mathrm{r}_{0} ; l=2 l_{0}$
2 $\mathrm{r}=2 \mathrm{r}_{0} ; l=l_{0}$
3 $\mathrm{r}=\mathrm{r}_{0} ; l=l_{0}$
4 $\mathrm{r}=\mathrm{r}_{0} ; l=2 l_{0}$
Heat Transfer

149350 A composite slab is prepared with two different materials $A$ and $B$. The relation between their coefficient of thermal conductivity and thickness is given as $K_{A}=\frac{K_{B}}{2}$ and $X_{A}=2 X_{B}$, respectively. If the temperature of faces of $A$ and $B$ are $75^{\circ} \mathrm{C}$ and $50^{\circ} \mathrm{C}$ respectively, what will be the temperature of common surface?

1 $75^{\circ} \mathrm{C}$
2 $50^{\circ} \mathrm{C}$
3 $55^{\circ} \mathrm{C}$
4 $125^{\circ} \mathrm{C}$
Heat Transfer

149351 Two thin metallic spherical shells of radii 20 $\mathrm{cm}$ and $30 \mathrm{~cm}$, respectively are placed with their centres coinciding. A material of thermal condutivity $\alpha$ is filled in the space between the shells. The inner shell is maintained at $300 \mathrm{~K}$ and the outer shell at $310 \mathrm{~K}$. If the rate at which heat flows radially through the material is $40 \mathrm{~W}$, find the value of $\alpha$ (in units of $\mathrm{J} \mathrm{s}^{-1} \mathrm{~m}^{-1}$ $\mathrm{K}^{-1}$ ).

1 $\frac{3}{\pi}$
2 $\frac{4 \pi}{3}$
3 $\frac{5}{3 \pi}$
4 $\frac{\pi}{2}$
NEET Test Series from KOTA - 10 Papers In MS WORD WhatsApp Here