MCQ
Two rectangular blocks, having indentical dimensions, can be arranged either in configuration $I$ or in configuration $II$ as shown in the figure, On of the blocks has thermal conductivity $k$ and the other $2 \ k$. The temperature difference between the ends along the $x$-axis is the same in both the configurations. It takes $9\ s$ to transport a certain amount of heat from the hot end to the cold end in the configuration $I$. The time to transport the same amount of heat in the configuration $II$ is :
  • $2.0 \ s$
  • B
    $3.0 \ s$
  • C
    $4.5 \ s$
  • D
    $6.0 \ s$

Answer

Correct option: A.
$2.0 \ s$
a
In configuration $1$ equivalent thermal resistance is $\frac{3 R}{2}$

In configuration $2$ equivalent thermal resistance is $\frac{R}{3}$ Thermal Resistance $\propto$ time taken by heat flow from high temperature to low temperature

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

A vessel containing $5\, litres$ of a gas at $0.8 \,pa$ pressure is connected to an evacuated vessel of volume $3$ litres. The resultant pressure inside will be ...... $pa$  (assuming whole system to be isolated)
The fundamental frequency of a sonometre wire is $n.$ If its radius is doubled and its tension becomes half, the material of the wire remains same, the new fundamental frequency will be
What happens to the centripetal acceleration of a revolving body if you double the orbital speed $v$ and half the angular velocity $\omega $
A rope is wound around a hollow cylinder of mass $3\, kg$ and radius $40\, cm.$ ........ $rad/sec^2$ is the angular acceleration of the cylinder if the rope is pulled with a force of $30\, N\,?$
Planet $A$ has mass $\mathrm{M}$ and radius $\mathrm{R}$. Planet $\mathrm{B}$ has half the mass and half the radius of Planet $A$. If the escape velocities from the Planets $A$ and $\mathrm{B}$ are $v_{\mathrm{A}}$ and $v_{\mathrm{B}},$ respectively, then $\frac{v_{\mathrm{A}}}{v_{\mathrm{B}}}=\frac{\mathrm{n}}{4}$ The value of $\mathrm{n}$ is
Kinetic theory of gases provide a base for
Instantaneous temperature difference between cooling body and the surroundings obeying Newton's law of cooling is $\theta$. Which of the following represents the variation of $\ln \theta$ with time $t$ ?
A cubical box with porous walls containing an equal number of ${O_2}$ and $H_2$ molecules is placed in a large evacuated chamber. The entire system is maintained at constant temperature $T.$ The ratio of ${v_{rms}}$ of ${O_2}$ molecules to that of the ${v_{rms}}$ of $H_2$ molecules, found in the chamber outside the box after a short interval is
The spectrum of a black body at two temperatures $27\,^oC$ and $327\,^oC$ is shown in the figure. Let $A_1$ and $A_2$ be the areas under the two curves respectively. Find the value of $\frac {A_2}{A_1}$
$A$ uniform cube of side $‘b’$ and mass $M$ rest on a rough horizontal table.$ A$ horizontal force $F$ is applied normal to one of the face at $a$ point, at $a$ height $3b/4$ above the base. What should be the coefficient of friction $(\mu )$ between cube and table so that is will tip about an edge before it starts slipping?