The heat transfer by conduction through a thick sphere is given by
A. $${\text{Q}} = \frac{{2\pi {\text{k}}{{\text{r}}_1}{{\text{r}}_2}\left( {{{\text{T}}_1} - {{\text{T}}_2}} \right)}}{{{{\text{r}}_2} - {{\text{r}}_1}}}$$
B. $${\text{Q}} = \frac{{4\pi {\text{k}}{{\text{r}}_1}{{\text{r}}_2}\left( {{{\text{T}}_1} - {{\text{T}}_2}} \right)}}{{{{\text{r}}_2} - {{\text{r}}_1}}}$$
C. $${\text{Q}} = \frac{{6\pi {\text{k}}{{\text{r}}_1}{{\text{r}}_2}\left( {{{\text{T}}_1} - {{\text{T}}_2}} \right)}}{{{{\text{r}}_2} - {{\text{r}}_1}}}$$
D. $${\text{Q}} = \frac{{8\pi {\text{k}}{{\text{r}}_1}{{\text{r}}_2}\left( {{{\text{T}}_1} - {{\text{T}}_2}} \right)}}{{{{\text{r}}_2} - {{\text{r}}_1}}}$$
Answer: Option B
Solution(By Examveda Team)
The heat transfer by conduction through a thick sphere is given by $${\text{Q}} = \frac{{4\pi {\text{k}}{{\text{r}}_1}{{\text{r}}_2}\left( {{{\text{T}}_1} - {{\text{T}}_2}} \right)}}{{{{\text{r}}_2} - {{\text{r}}_1}}}.$$This Question Belongs to Mechanical Engineering >> Heat And Mass Transfer
The heat is transferred by conduction, convection and radiation in
A. Melting of ice
B. Boiler furnaces
C. Condensation of steam in condenser
D. None of these
Heat is transferred by all three modes of transfer, viz. conduction, convection and radiation in
A. Electric heater
B. Steam condenser
C. Boiler
D. Refrigerator condenser coils
The radiation emitted by a black body is known as
A. Black radiation
B. Full radiation
C. Total radiation
D. All of these
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