Download App

STD 11 - 10.2 , transmission of heat — JEE STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 ScienceJEESTD 11 - 10.2 , transmission of heat4 Marks
MCQ
Three rods made of the same material and having the same cross section have been joined as shown in the figure. Each rod is of the same length. The left and right ends are kept at ${0^o}C$ and ${90^o}C$ respectively. The temperature of the junction of the three rods will be ...... $^oC$
  • A
    $45$
  • ✓
    $60$
  • C
    $30$
  • D
    $20$
✓

Answer

Correct option: B.
$60$
b
(b) Let the temperature of junction be $\theta$. Since roads $B$ and $C$ are parallel to each other (because both having the same temperature difference).

Hence given figure can be redrawn as follows
( $\frac{Q}{t} = \frac{{({\theta _1} - {\theta _2})}}{R}$ and ${\left( {\frac{Q}{t}} \right)_{AB}} = {\left( {\frac{Q}{t}} \right)_{BC}}$

==> $\frac{{(90 - \theta )}}{{R/2}} = \frac{{(\theta - 0)}}{R}$

==> $180 - 2\theta = \theta $

==>$\theta = 60^\circ C$

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

Explore more

JEE STD 11 Science question papers→Gujarat Board STD 11 Science question papers→Gujarat Board question paper generator→

Similar questions

The $50\,kg$ homogeneous smooth sphere rests on the $30^{\circ}$ incline $A$ and bears against the smooth vertical wall $B$. Calculate the contact forces at $A$ and $B.$
→
A body weight $500 \,N$ on the surface of the earth. How much would it weigh half way below the surface of the earth ....... $N$
→
Two springs with spring constants ${K_1} = 1500\,N/m$ and ${K_2} = 3000\,N/m$ are stretched by the same force. The ratio of potential energy stored in spring will be
→
A horizontal parallel beam of light passes through a vertical convex lens of focal length $20 \,cm$ and is then reflected by a tilted plane mirror, so that it converges to a point $I$. The distance $P I$ is $10 \,cm$. $M$ is a point at which the axis of the lens intersects the mirror. The distance $P M$ is $10 \,cm$. The angle which the mirror makes with the horizontal is
→
Each atom of an iron bar $(5\,cm \times 1\,cm \times 1\,cm)$ has a magnetic moment $1.8 \times {10^{ - 23}}\,A{m^2}.$ Knowing that the density of iron is $7.78 \times {10^3}\,k{g^{ - 3}}\,m,$ atomic weight is $56$ and Avogadro's number is $6.02 \times {10^{23}}$ the magnetic moment of bar in the state of magnetic saturation will be.....$A{m^2}$
→
The minimum frequency $\nu $ of continuous $X-$ rays is related to the applied potential difference $V$ as
→
A source $S_1$ is producing, $10^{15}$ photons per second of wavelength $5000 \;\mathring A.$ Another source $S_2$ is producing $1.02 \times 10^{15}$ photons per second of wavelength $5100\;\mathring A$. Then, $($ power of $S_2)/$  $($ power of $S_1)$ is equal to
→
A bottle has an opening of radius $a$ and length $b$. A cork of length band radius $\left( {a + \Delta a} \right)$ where $\left( {\Delta a <  < a} \right)$ is compressed to fit into the opening completely (see figure). If the bulk modulus of cork is $B$ and frictional coefficient between the bottle and cork is $\mu $ then the force needed to push the cork into the bottle is
→
A radioactive nucleus of mass $M$ emits a photon of frequency $f$ and the nucleus recoils. The recoil energy will be
→
Two positive charges of $20$ $coulomb$ and $Q\;coulomb$ are situated at a distance of $60\,cm$. The neutral point between them is at a distance of $20\,cm$ from the $20\,coulomb$ charge. Charge $Q$ is.....$C$
→