Two bars of thermal conductivities K and 3K and lengths 1 cm and 2 cm respectively have equal cross-sectional area, they are joined lengths wise as shown in the figure. If the temperature at the ends of this composite bar is 0°C and 100°C respectively (see figure), then the temperature ϕ of the interface is

(1) 50°C     
               
(2) 1003°C 

(3) 60°C   
                 
(4) 2003°C 

Subtopic:  Conduction |
 75%
From NCERT
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

A heat flux of 4000 J/s is to be passed through a copper rod of length 10 cm and area of cross-section 100 cm2. The thermal conductivity of copper is 400 W/m°C. The two ends of this rod must be kept at a temperature difference of 
(1) 1°C                

(2) 10°C

(3) 100°C             

(4) 1000°C 

Subtopic:  Conduction |
 75%
From NCERT
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

On a cold morning, a metal surface will feel colder to touch than a wooden surface because 

(1) Metal has high specific heat

(2) Metal has high thermal conductivity

(3) Metal has low specific heat

(4) Metal has low thermal conductivity

Subtopic:  Conduction |
 71%
From NCERT
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

At a common temperature, a block of wood and a block of metal feel equally cold or hot. The temperatures of block of wood and block of metal are 

(1) Equal to temperature of the body

(2) Less than the temperature of the body

(3) Greater than temperature of the body

(4) Either (b) or (c)

Subtopic:  Conduction |
 51%
From NCERT
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

The coefficient of thermal conductivity of copper is nine times that of steel. In the composite cylindrical bar shown in the figure. What will be the temperature at the junction of copper and steel 


(a) 75°C
(b) 67°C
(c) 33°C
(d) 25°C

Subtopic:  Conduction |
 77%
From NCERT
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

A slab consists of two parallel layers of two different materials of same thickness having thermal conductivities K1 and K2. The equivalent conductivity of the combination is

(1) K1+K2           

(2) K1+K22

(3) 2K1K2K1+K2         

(4) K1+K22K1K2

Subtopic:  Conduction |
 68%
From NCERT
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
Links
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

There are two identical vessels filled with equal amounts of ice. The vessels are of different metals., If the ice melts in the two vessels in 20 and 35 minutes respectively, the ratio of the coefficients of thermal conductivity of the two metals is

(1) 4 : 7                   

(2) 7 : 4

(3) 16 :49                 

(4) 49 : 16

Subtopic:  Conduction |
 84%
From NCERT
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

Heat current is maximum in which of the following (rods are of identical dimension) ?

Subtopic:  Conduction |
 65%
From NCERT
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

Consider a compound slab consisting of two different materials having an equal thickness and thermal conductivities K and 2K respectively. The equivalent thermal conductivity of the slab if the materials are joined by ends is:
(a) 2K                  (b) 3K
(c) 43K                    (d) 23K

Subtopic:  Conduction |
 73%
From NCERT
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

Two rods having thermal conductivity in the ratio of 5 : 3 having equal lengths and equal cross-sectional area are joined by face to face. If the temperature of the free end of the first rod is 100°C and free end of the second rod is 20°C. Then temperature of the junction is

(1) 70 °C                   

(2) 50 °C

(3) 50 °C                  

(4) 90 °C

Subtopic:  Conduction |
 81%
From NCERT
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh