Multiple choice

Why does the bi-metal rod of iron and brass bend when it is heated?

  1. Specific heat of iron and brass is the reason for this

  2. Their coefficient of linear expansion is different

  3. When heated, their temperature do not remain the same

  4. Iron and brass become soft when heated
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A bi-metal rod bends when heated because the two metals have different coefficients of linear expansion. One metal expands more than the other for the same temperature increase, causing the composite rod to curve toward the side with less expansion. This principle is used in thermostats and temperature-control devices.

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