Two conducting slabs of heat conductivity $$K_{1} ~\text{and}~K_{2}$$ are joined as shown in figure. If the temperature at the ends of the slabs are $$\theta_{1}~\text{and}~\theta_{2} \ (\theta_{1} > \theta_{2} ),$$ then the final temperature $$\left(\theta\right)_{m}$$ of the junction will be:

 1 $$\frac{K_{1} \theta_{1} + K_{2} \theta_{2}}{K_{1} + K_{2}}$$ 2 $$\frac{K_{1} \theta_{2} + K_{2} \theta_{1}}{K_{1} + K_{2}}$$ 3 $$\frac{K_{1} \theta_{2} + K_{2} \theta_{1}}{K_{1} - K_{2}}$$ 4 None
Subtopic:  Conduction |
83%
From NCERT
AIPMT - 1999
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

A cylindrical rod has temperatures ${\mathrm{T}}_{1}$ $\mathrm{and}$ ${\mathrm{T}}_{2}$ at its ends. The rate of flow of heat is ${Q}_{1}$ cal/sec. If all the linear dimensions are doubled while keeping the temperature constant, then the rate of flow of heat ${Q}_{2}$ will be:

1. $4{Q}_{1}$

2. $2{Q}_{1}$

3. $\frac{{Q}_{1}}{4}$

4. $\frac{{Q}_{1}}{2}$

Subtopic:  Conduction |
74%
From NCERT
AIPMT - 2001
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

Consider two rods of the same length and different specific heats $$(S_1,S_2)$$ conductivities $$(K_1,K_2)$$ and area of cross-sections $$(A_1,A_2)$$ and both having temperature $$T_1$$ and $$T_2$$ at their ends. If the rate of loss of heat due to conduction is equal, then:
1. $$K_1A_1=K_2A_2$$
2. $$\frac{K_1A_1}{S_1}=\frac{K_2A_2}{S_2}$$
3. $$K_2A_1=K_1A_2$$
4. $$\frac{K_2A_1}{S_2}=\frac{K_1A_2}{S_1}$$

Subtopic:  Conduction |
73%
From NCERT
AIPMT - 2002
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

Consider a compound slab consisting of two different materials having equal thicknesses and thermal conductivities K and 2K, respectively. The equivalent thermal conductivity of the slab will be:

 1 $2/6$$\mathrm{K}$ 2 $\sqrt{2}$$\mathrm{K}$ 3 $3\mathrm{K}$ 4 $4/3$$\mathrm{K}$
Subtopic:  Conduction |
71%
From NCERT
AIPMT - 2003
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

The temperature of inversion of a thermocouple is 620ºC and the neutral temperature is 300ºC. What is the temperature of the cold junction:

1. 40ºC

2. 20ºC

3. 320ºC

4. –20ºC

Subtopic:  Conduction |
AIPMT - 2005
Hints

Which of the following circular rods, (given radius $$r$$ and length $$l$$) each made of the same material and whose ends are maintained at the same temperature will conduct the most heat:

 1 $$r=2r_0;~l=2l_0$$ 2 $$r=2r_0;~l=l_0$$ 3 $$r=r_0;~l=2l_0$$ 4 $$r=r_0;~l=l_0$$
Subtopic:  Conduction |
85%
From NCERT
AIPMT - 2005
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch