Properties of Solids & LiquidsHeat Transfer (NEET (NTANational Eligibility cum Medical Entrance Test) Physics): Questions 32  34 of 40
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Question number: 32
» Properties of Solids & Liquids » Heat Transfer » Conduction
Question
An ice box used for keeping eatable cold has a total wall, area of 1 metre ^{2} and a wall thickness of 5.0 cm. The thermal conductivity of the ice box is K = 0.01 joule/meter °C. is filled with ice at 0° C along with eatables on a day when the temperature is 40°C. The latent heat of fusion of ice is 334 × 10 ^{3} joules/kg. The amount of ice melted in one day is (1 day = 86400 seconds)
Choices
Choice (4)  Response  

a.  7760 gm 

b.  1552 gm 

c.  2776 gm 

d.  2069 gm 

Question number: 33
» Properties of Solids & Liquids » Heat Transfer » Radiation
Question
Two bodies A and B have thermal emissivity of 0.01 and 0.81 respectively. The outer surface areas of the two bodies are the same. The two bodies emit total radiant power at the same rate. The wavelength λ _{B} corresponding to maximum spectral radiance in the radiation from B is shifted from the wavelength corresponding to maximum spectral radiance in the radiation from A, by 1.00 µm. If the temperature of A is 5802 K
(1) The temperature of B is 1934 K
(2) λ _{B} = 1.5 μm
(3) The temperature of B is 11604 K
(4) The temperature of B is 2901 K
Select the correct answers and mark it according to the following codes:
Choices
Choice (4)  Response  

a.  1 and 3 are correct 

b.  1 and 2 are correct 

c.  1, 2 and 3 are correct 

d.  2 and 4 are correct 

Question number: 34
» Properties of Solids & Liquids » Heat Transfer » Radiation
Question
A body cools from 90° C to 50° C in 10 minutes. If the room temperature is 25° C and assuming Newton’s law of cooling to hold good, the temperature of the body at the end of the next 10 minutes will be
Choices
Choice (4)  Response  

a.  56.40° C 

b.  34.61° C 

c.  46.75° C 

d.  42.85° C 
