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JEE Main · 2021 · 16 Mar 2021 · Shift 2 · Heat & Thermodynamics

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A bimetallic strip consists of metals A and B . It is mounted rigidly as shown. The metal A has higher coefficient of expansion compared to that metal B . When bimetallic strip is placed in a cold bath, it will
  1. (A)Neither bend nor shrink
  2. (B)Not bend but shrink
  3. (C)Bend towards the left✓ Correct
  4. (D)Bend to wards the right

Answer: (C)

Solution

Both strips contract when cooled, and for the same fall in temperature the metal with the larger coefficient of linear expansion contracts more. Metal A therefore ends up shorter than metal B. The two are bonded along their whole length and cannot slide over each other, so the only way to accommodate the difference is for the pair to curve, with the shorter strip A on the inner side of the arc. Metal A lies on the left of the mounted strip, so in a cold bath the strip bends towards the left.

JEE Main · 2021 · 16 Mar 2021 · Shift 2 · Single correct option

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