The only possibility of heat flow in a thermos flask is through its cork which is $75 cm^2$ in area and $5 cm$ thick. Its thermal conductivity is $0.0075 cal/cmsec^oC$. The outside temperature is$ 40^oC$ and latent heat of ice is $80 cal g^{-1}$. Time taken by $500 g$ of ice at $0^oC$ in the flask to melt into water at $0^oC$ is ....... $hr$
The only possibility of heat flow in a thermos flask is through its cork which is $75 cm^2$ in area and $5 cm$ thick. Its thermal conductivity is $0.0075 cal/cmsec^oC$. The outside temperature is$ 40^oC$ and latent heat of ice is $80 cal g^{-1}$. Time taken by $500 g$ of ice at $0^oC$ in the flask to melt into water at $0^oC$ is ....... $hr$
- A
$2.47$
- B
$4.27 $
- C
$7.42 $
- D
$4.72$
Similar Questions
Two identical square rods of metal are welded end to end as shown in figure $(i)$ , $20$ calories of heat flows through it in $4$ minutes. If the rods are welded as shown in figure $(ii)$, the same amount of heat will flow through the rods in ....... $\min.$
Two identical square rods of metal are welded end to end as shown in figure $(i)$ , $20$ calories of heat flows through it in $4$ minutes. If the rods are welded as shown in figure $(ii)$, the same amount of heat will flow through the rods in ....... $\min.$
The two ends of a rod of length $L$ and a uniform cross-sectional area $A$ are kept at two temperatures $T_1$ and $T_2 (T_1 > T_2)$. The rate of heat transfer,$\frac{ dQ }{dt}$, through the rod in a steady state is given by
The two ends of a rod of length $L$ and a uniform cross-sectional area $A$ are kept at two temperatures $T_1$ and $T_2 (T_1 > T_2)$. The rate of heat transfer,$\frac{ dQ }{dt}$, through the rod in a steady state is given by
- [AIIMS 2019]
A metallic prong consists of $4$ rods made of the same material, cross-sections and same lengths as shown below. The three forked ends are kept at $100^{\circ} C$ and the handle end is at $0^{\circ} C$. The temperature of the junction is ............. $^{\circ} C$
A metallic prong consists of $4$ rods made of the same material, cross-sections and same lengths as shown below. The three forked ends are kept at $100^{\circ} C$ and the handle end is at $0^{\circ} C$. The temperature of the junction is ............. $^{\circ} C$
- [KVPY 2013]
Radius of a conductor increases uniformly from left end to right end as shown in fig.Material of the conductor is isotropic and its curved surface is thermally isolated from surrounding. Its ends are maintained at temperatures $T_1$ and $T_2$ ($T_1$ > $T_2$): If, in steady state, heat flow rate is equal to $H$ , then which of the following graphs is correct
A hollow sphere of inner radius $R$ and outer radius $2R$ is made of a material of thermal conductivity $K$. It is surrounded by another hollow sphere of inner radius $2R$ and outer radius $3R$ made of same material of thermal conductivity $K$. The inside of smaller sphere is maintained at $0^o C$ and the outside of bigger sphere at $100^o C$. The system is in steady state. The temperature of the interface will be ........ $^oC$
A hollow sphere of inner radius $R$ and outer radius $2R$ is made of a material of thermal conductivity $K$. It is surrounded by another hollow sphere of inner radius $2R$ and outer radius $3R$ made of same material of thermal conductivity $K$. The inside of smaller sphere is maintained at $0^o C$ and the outside of bigger sphere at $100^o C$. The system is in steady state. The temperature of the interface will be ........ $^oC$