00. Conduction
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Heat Transfer

149372 Consider a pair of insulating blocks with thermal resistances $R_{1}$ and $R_{2}$ as shown in the figure. The temperature $\theta$ at the boundary between the two blocks is

1 $\left(\theta_{1} \theta_{2} \sqrt{ } \mathrm{R}_{1} \mathrm{R}_{2}\right) /\left(\theta_{1}+\theta_{2}\right)\left(\mathrm{R}_{1}+\mathrm{R}_{2}\right)$
2 $\left(\theta_{1} \mathrm{R}_{1}+\theta_{2} \mathrm{R}_{2}\right) /\left(\mathrm{R}_{1}+\mathrm{R}_{2}\right)$
3 $\left[\left(\theta_{1}+\theta_{2}\right) \mathrm{R}_{1} \mathrm{R}_{2}\right] /\left(\mathrm{R}_{1}{ }^{2}+\mathrm{R}_{2}{ }^{2}\right)$
4 $\left(\theta_{1} \mathrm{R}_{2}+\theta_{2} \mathrm{R}_{1}\right) /\left(\mathrm{R}_{1}+\mathrm{R}_{2}\right)$
VITEEE-2019
Heat Transfer

149373 Six identical conducting rods are joined as shown in figure. Points $A$ and $D$ are maintained at $200^{\circ} \mathrm{C}$ and $20^{\circ} \mathrm{C}$ respectively. The temperature of junction $B$ will be

1 $120^{\circ} \mathrm{C}$
2 $100^{\circ} \mathrm{C}$
3 $140^{\circ} \mathrm{C}$
4 $80^{\circ} \mathrm{C}$
VITEEE-2017]
Heat Transfer

149374 A copper wire of length $1000 \mathrm{~m}$ and crosssectional area $1 \mathrm{~mm}^{2}$ carries a current $4.5 \mathrm{~A}$. Assume that each copper atom contributes one conduction electron. What is the speed of propagation of electric field along the conductor which causes the drift motion? [density of copper is $9.0 \times 10^{3} \mathrm{~kg} \mathrm{~m}^{-3}$ and atomic mass is 63.5]

1 $3.0 \times 10^{-3} \mathrm{~m} / \mathrm{s}$
2 $3.0 \times 10^{-4} \mathrm{~m} / \mathrm{s}$
3 $3.0 \times 10^{8} \mathrm{~m} / \mathrm{s}$
4 $3.0 \times 10^{10} \mathrm{~m} / \mathrm{s}$
SCRA-2011
Heat Transfer

149375 Four metallic rods of same material but of different dimensions are placed between two constant temperature baths of different temperatures. Which of the rods having the following dimensions will conduct maximum heat between the temperature baths?

1 Length is $100 \mathrm{~cm}$ and radius is $1 \mathrm{~cm}$
2 Length is $200 \mathrm{~cm}$ and radius is $2 \mathrm{~cm}$
3 Length is $200 \mathrm{~cm}$ and radius is $1 \mathrm{~cm}$
4 Length is $100 \mathrm{~cm}$ and radius is $2 \mathrm{~cm}$
SCRA-2010
NEET DIGITAL LIBRARY
Heat Transfer

149372 Consider a pair of insulating blocks with thermal resistances $R_{1}$ and $R_{2}$ as shown in the figure. The temperature $\theta$ at the boundary between the two blocks is

1 $\left(\theta_{1} \theta_{2} \sqrt{ } \mathrm{R}_{1} \mathrm{R}_{2}\right) /\left(\theta_{1}+\theta_{2}\right)\left(\mathrm{R}_{1}+\mathrm{R}_{2}\right)$
2 $\left(\theta_{1} \mathrm{R}_{1}+\theta_{2} \mathrm{R}_{2}\right) /\left(\mathrm{R}_{1}+\mathrm{R}_{2}\right)$
3 $\left[\left(\theta_{1}+\theta_{2}\right) \mathrm{R}_{1} \mathrm{R}_{2}\right] /\left(\mathrm{R}_{1}{ }^{2}+\mathrm{R}_{2}{ }^{2}\right)$
4 $\left(\theta_{1} \mathrm{R}_{2}+\theta_{2} \mathrm{R}_{1}\right) /\left(\mathrm{R}_{1}+\mathrm{R}_{2}\right)$
VITEEE-2019
Heat Transfer

149373 Six identical conducting rods are joined as shown in figure. Points $A$ and $D$ are maintained at $200^{\circ} \mathrm{C}$ and $20^{\circ} \mathrm{C}$ respectively. The temperature of junction $B$ will be

1 $120^{\circ} \mathrm{C}$
2 $100^{\circ} \mathrm{C}$
3 $140^{\circ} \mathrm{C}$
4 $80^{\circ} \mathrm{C}$
VITEEE-2017]
Heat Transfer

149374 A copper wire of length $1000 \mathrm{~m}$ and crosssectional area $1 \mathrm{~mm}^{2}$ carries a current $4.5 \mathrm{~A}$. Assume that each copper atom contributes one conduction electron. What is the speed of propagation of electric field along the conductor which causes the drift motion? [density of copper is $9.0 \times 10^{3} \mathrm{~kg} \mathrm{~m}^{-3}$ and atomic mass is 63.5]

1 $3.0 \times 10^{-3} \mathrm{~m} / \mathrm{s}$
2 $3.0 \times 10^{-4} \mathrm{~m} / \mathrm{s}$
3 $3.0 \times 10^{8} \mathrm{~m} / \mathrm{s}$
4 $3.0 \times 10^{10} \mathrm{~m} / \mathrm{s}$
SCRA-2011
Heat Transfer

149375 Four metallic rods of same material but of different dimensions are placed between two constant temperature baths of different temperatures. Which of the rods having the following dimensions will conduct maximum heat between the temperature baths?

1 Length is $100 \mathrm{~cm}$ and radius is $1 \mathrm{~cm}$
2 Length is $200 \mathrm{~cm}$ and radius is $2 \mathrm{~cm}$
3 Length is $200 \mathrm{~cm}$ and radius is $1 \mathrm{~cm}$
4 Length is $100 \mathrm{~cm}$ and radius is $2 \mathrm{~cm}$
SCRA-2010
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Heat Transfer

149372 Consider a pair of insulating blocks with thermal resistances $R_{1}$ and $R_{2}$ as shown in the figure. The temperature $\theta$ at the boundary between the two blocks is

1 $\left(\theta_{1} \theta_{2} \sqrt{ } \mathrm{R}_{1} \mathrm{R}_{2}\right) /\left(\theta_{1}+\theta_{2}\right)\left(\mathrm{R}_{1}+\mathrm{R}_{2}\right)$
2 $\left(\theta_{1} \mathrm{R}_{1}+\theta_{2} \mathrm{R}_{2}\right) /\left(\mathrm{R}_{1}+\mathrm{R}_{2}\right)$
3 $\left[\left(\theta_{1}+\theta_{2}\right) \mathrm{R}_{1} \mathrm{R}_{2}\right] /\left(\mathrm{R}_{1}{ }^{2}+\mathrm{R}_{2}{ }^{2}\right)$
4 $\left(\theta_{1} \mathrm{R}_{2}+\theta_{2} \mathrm{R}_{1}\right) /\left(\mathrm{R}_{1}+\mathrm{R}_{2}\right)$
VITEEE-2019
Heat Transfer

149373 Six identical conducting rods are joined as shown in figure. Points $A$ and $D$ are maintained at $200^{\circ} \mathrm{C}$ and $20^{\circ} \mathrm{C}$ respectively. The temperature of junction $B$ will be

1 $120^{\circ} \mathrm{C}$
2 $100^{\circ} \mathrm{C}$
3 $140^{\circ} \mathrm{C}$
4 $80^{\circ} \mathrm{C}$
VITEEE-2017]
Heat Transfer

149374 A copper wire of length $1000 \mathrm{~m}$ and crosssectional area $1 \mathrm{~mm}^{2}$ carries a current $4.5 \mathrm{~A}$. Assume that each copper atom contributes one conduction electron. What is the speed of propagation of electric field along the conductor which causes the drift motion? [density of copper is $9.0 \times 10^{3} \mathrm{~kg} \mathrm{~m}^{-3}$ and atomic mass is 63.5]

1 $3.0 \times 10^{-3} \mathrm{~m} / \mathrm{s}$
2 $3.0 \times 10^{-4} \mathrm{~m} / \mathrm{s}$
3 $3.0 \times 10^{8} \mathrm{~m} / \mathrm{s}$
4 $3.0 \times 10^{10} \mathrm{~m} / \mathrm{s}$
SCRA-2011
Heat Transfer

149375 Four metallic rods of same material but of different dimensions are placed between two constant temperature baths of different temperatures. Which of the rods having the following dimensions will conduct maximum heat between the temperature baths?

1 Length is $100 \mathrm{~cm}$ and radius is $1 \mathrm{~cm}$
2 Length is $200 \mathrm{~cm}$ and radius is $2 \mathrm{~cm}$
3 Length is $200 \mathrm{~cm}$ and radius is $1 \mathrm{~cm}$
4 Length is $100 \mathrm{~cm}$ and radius is $2 \mathrm{~cm}$
SCRA-2010
For More Updates join with Us
Heat Transfer

149372 Consider a pair of insulating blocks with thermal resistances $R_{1}$ and $R_{2}$ as shown in the figure. The temperature $\theta$ at the boundary between the two blocks is

1 $\left(\theta_{1} \theta_{2} \sqrt{ } \mathrm{R}_{1} \mathrm{R}_{2}\right) /\left(\theta_{1}+\theta_{2}\right)\left(\mathrm{R}_{1}+\mathrm{R}_{2}\right)$
2 $\left(\theta_{1} \mathrm{R}_{1}+\theta_{2} \mathrm{R}_{2}\right) /\left(\mathrm{R}_{1}+\mathrm{R}_{2}\right)$
3 $\left[\left(\theta_{1}+\theta_{2}\right) \mathrm{R}_{1} \mathrm{R}_{2}\right] /\left(\mathrm{R}_{1}{ }^{2}+\mathrm{R}_{2}{ }^{2}\right)$
4 $\left(\theta_{1} \mathrm{R}_{2}+\theta_{2} \mathrm{R}_{1}\right) /\left(\mathrm{R}_{1}+\mathrm{R}_{2}\right)$
VITEEE-2019
Heat Transfer

149373 Six identical conducting rods are joined as shown in figure. Points $A$ and $D$ are maintained at $200^{\circ} \mathrm{C}$ and $20^{\circ} \mathrm{C}$ respectively. The temperature of junction $B$ will be

1 $120^{\circ} \mathrm{C}$
2 $100^{\circ} \mathrm{C}$
3 $140^{\circ} \mathrm{C}$
4 $80^{\circ} \mathrm{C}$
VITEEE-2017]
Heat Transfer

149374 A copper wire of length $1000 \mathrm{~m}$ and crosssectional area $1 \mathrm{~mm}^{2}$ carries a current $4.5 \mathrm{~A}$. Assume that each copper atom contributes one conduction electron. What is the speed of propagation of electric field along the conductor which causes the drift motion? [density of copper is $9.0 \times 10^{3} \mathrm{~kg} \mathrm{~m}^{-3}$ and atomic mass is 63.5]

1 $3.0 \times 10^{-3} \mathrm{~m} / \mathrm{s}$
2 $3.0 \times 10^{-4} \mathrm{~m} / \mathrm{s}$
3 $3.0 \times 10^{8} \mathrm{~m} / \mathrm{s}$
4 $3.0 \times 10^{10} \mathrm{~m} / \mathrm{s}$
SCRA-2011
Heat Transfer

149375 Four metallic rods of same material but of different dimensions are placed between two constant temperature baths of different temperatures. Which of the rods having the following dimensions will conduct maximum heat between the temperature baths?

1 Length is $100 \mathrm{~cm}$ and radius is $1 \mathrm{~cm}$
2 Length is $200 \mathrm{~cm}$ and radius is $2 \mathrm{~cm}$
3 Length is $200 \mathrm{~cm}$ and radius is $1 \mathrm{~cm}$
4 Length is $100 \mathrm{~cm}$ and radius is $2 \mathrm{~cm}$
SCRA-2010