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Four conducting rods are joined to make a square. All rods are identical and ends $A, B$ and $C$ are maintained at given temperatures. choose $INCORRECT$ statement for given arrangement in steady state. (value of $\frac {KA}{L}$ is $1\frac{J}{{{S^o}C}}$ , symbols , have their usual meaning)
The rate of loss of heat from a body cooling under conditions of forced convection is proportional to its $(A)$ heat capacity $(B)$ surface area $(C)$ absolute temperature $(D)$ excess of temperature over that of surrounding : state if
In the Arctic region, hemispherical houses called Igloos are made of ice. It is possible to maintain a temperature inside an Igloo as high as $20^{\circ} C$ because
Four spheres $A, B, C$ and $D$ are of same radius but made of different metals. Their densities are in ratio $6 : 3 : 4 : 5$ and specific heats are in ratio $2 : 5 : 4 : 6$ . These are initially kept at the same temperature and placed in the same surroundings. The sphere which has the slowest rate of cooling is
A cup of tea cools from $65.5^o C to 62.5 ^o C$ in one minute in a room of $22.5 ^o C$. How long will the same cup of tea take, in.............. minutes, to cool from $46.50^o C to 40.5 ^o C$ in the same room ? (choose nearest value)
A body cools in a surrounding which is at a constant temperature of ${\theta _0}$. Assume that it obeys Newton's law of cooling. Its temperature $\theta $ is plotted against time $t$ . Tangents are drawn to the curve at the points $P(\theta = {\theta _1})$ and $Q(\theta = {\theta _2})$. These tangents meet the time axis at angles of ${\varphi _2}$and ${\varphi _1}$, as shown
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 area of a hole of heat furnace is ${10^{ - 4}}{m^2}$. It radiates $1.58 \times {10^5}$ calories of heat per hour. If the emissivity of the furnace is $0.80$ , then its temperature is....... $K$
A liquid in a beaker has temperature $\theta (t)$ at time $t$ and $\theta_0$ is temperature of surroundings, then according to Newton's law of cooling the correct graph between loge $log_e(\theta - \theta_0) $ and $t$ is