Three rods of identical dimensions but made of materials of conductivities \(K,~2K,~K\) are connected in series. The two ends \(A~,B\) are maintained at temperatures of \(0~^{\circ} \text{C},~100~^{\circ} \text{C}\) respectively. Assume no loss of heat from the sides. The temperatures of the junctions \(X,~Y\) are:
                  
1. \(25~^\circ\text C,~75~^\circ\text C\)
2. \(40~^\circ\text C,~60~^\circ\text C\)
3. \(20~^\circ\text C,~80~^\circ\text C\)
4. \(30~^\circ\text C,~70~^\circ\text C\)
Subtopic:  Conduction |
 70%
From NCERT
Please attempt this question first.
Hints
Please attempt this question first.

If the ends of the meter stick are maintained at \(\theta_1\)\(^\circ \text{C}\) and \(\theta_2\)\(^\circ \text{C},\) the temperatures measured at the \(25\) cm and \(80\) cm marks are observed to be \(35^\circ \text{C}\) and \(68^\circ \text{C}\) respectively. Then the temperatures of the left end (\(\theta_1\)\(^\circ \text{C}\)) and the right end (\(\theta_2\)\(^\circ \text{C}\)) are: 
1. \(\theta_{1}=0, ~\theta_{2}=90\)   
2. \(\theta_{1}=10,~\theta_{2}=85\)
3. \(\theta_{1}=20, ~\theta_{2}=80\)
4. \(\theta_{1}=30, ~\theta_{2}=100\)
Subtopic:  Conduction |
 70%
From NCERT
Please attempt this question first.
Hints
Please attempt this question first.

Two rods of identical dimensions are joined end-to-end, and the ends of the composite rod are kept at \(0^\circ\text{C}\) and \(100^\circ\text{C}\) (as shown in the diagram). The temperature of the joint is found to be \(40^\circ\text{C}.\) Assuming no loss of heat through the sides of the rods, the ratio of the conductivities of the rods \(\dfrac{K_1}{K_2}\) is:
                      
1. \(\dfrac32\)
2. \(\dfrac23\)
3. \(\dfrac11\)
4. \(\dfrac{\sqrt3}{\sqrt2}\)

Subtopic:  Conduction |
 79%
From NCERT
Please attempt this question first.
Hints
Please attempt this question first.

advertisementadvertisement

Two rods \(A\) and \(B\) of different materials are welded together as shown in the figure. Their thermal conductivities are \(K_1\) and \(K_2.\) The thermal conductivity of the composite rod will be:
            

1. \(\frac{3(K_1+K_2)}{2}\) 2. \(K_1+K_2\)
3. \(2(K_1+K_2)\) 4. \(\frac{(K_1+K_2)}{2}\)
Subtopic:  Conduction |
 73%
From NCERT
NEET - 2017
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
Links
To view explanation, please take trial in the course.
NEET 2025 - Target Batch