Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
JEE Main202117 Mar 2021Morning ShiftPhysicsThermal Properties of MatterActual

Two identical metal wires of thermal conductivities K 1 and K 2 respectively are connected in series. The effective thermal conductivity of the combination is:

Options

  1. A2   K 1   K 2   K 1 + K 2
  2. BK 1 + K 2 2   K 1   K 2
  3. CK 1 + K 2   K 1   K 2
  4. DK 1   K 2   K 1 + K 2

Correct answer

A. 2   K 1   K 2   K 1 + K 2

Step-by-step solution

R e f f = l   K 1   A + l   K 2   A = 2 l   K e q A K e q = 2   K 1   K 2   K 1 + K 2

Practice Thermal Properties of Matter on Quantrex Academy →

More from Thermal Properties of Matter

As shown in the figure, an insulated container is fitted with a thermally conducting but immovable partition (P₁) and a freely movable but thermally insulated piston (P₂) . The par 2026The heat extracted out of x gram of water initially at 50°C to cool it down to 0°C is sufficient to evaporate (1000 - x) gram of water also initially at 50°C . The value of x (clos 2026The temperature of a metal strip having coefficient of linear expansion is increased from T₁ to T₂ resulting in increase of its length by L₁ . The temperature is further increased 2026Which of the following best represents the temperature versus heat supplied graph for water, in the range of -20^ C to 120^ C ? 202610 kg of ice at -10^ C is added to 100 kg of water to lower its temperature from 25 ^ C . Consider no heat exchange to surroundings. The decrement to the temperature of water is _ 2026A brass wire of length 2 m and radius 1 mm at 27^ C is held taut between two rigid supports. Initially it was cooled to a temperature of -43^ C creating a tension T in the wire. Th 2026Rods x and y of equal dimensions but of different materials are joined as shown in figure. Temperatures of end points A and F are maintained at 100^ C and 40^ C respectively. Given 2026An aluminium and steel rods having same lengths and cross-sections are joined to make total length of 120 cm at 30^ C . The coefficient of linear expansion of aluminium and steel a 2026 Full Thermal Properties of Matter list All JEE Main PYQs