JEE Main 2019 (Online) 12th January Morning Slot | Heat and Thermodynamics Question 384 | Physics

A cylinder of radius R is surrounded by a cylindrical shell of inner radius R and outer radius 2R. The thermal conductivity of the material of the inner cylinder is K₁ and the of the outer cylinder is K₂. Assuming no loss of heat, the effective thermal conductivity of the system for heat flowing along the length of the cylinder is :

K₁ + K₂

$${{{K_1} + 3{K_2}} \over 4}$$

$${{{K_1} + {K_2}} \over 2}$$

$${{2{K_1} + 3{K_2}} \over 5}$$

JEE Main 2019 (Online) 12th January Morning Slot

MCQ (Single Correct Answer)

-1

An ideal gas occupies a volume of 2m³ at a pressure of 3 $$ \times $$ 10⁶ Pa. The energy of the gas is :

6 $$ \times $$ 10⁴ J

9$$ \times $$ 10⁶ J

3 $$ \times $$ 10² J

10⁸ J

JEE Main 2019 (Online) 11th January Evening Slot

MCQ (Single Correct Answer)

-1

Two rods A and B of identical dimensions are at temperature 30^°C. If A is heated upto 180^oC and B upto T^oC, then the new lengths are the same. If the ratio of the coefficients of linear expansion of A and B is 4 : 3, then the value of T is

200^oC

270^oC

230^oC

250^oC

JEE Main 2019 (Online) 11th January Evening Slot

MCQ (Single Correct Answer)

-1

A thermometer graduated according to a linear scale reads a value x₀ when in contact with boiling water, and x₀/3 when in contact with ice. What is the temperature of an object in ^oC, if this thermometer in the contact with the object reads x₀/2 ?