Question

Two copper rods P, Q of thickness in the ratio 2 : 5 taken. If both the rods P, Q of lengths 10 cm are heated to same temperature rise, then the ratio of the linear expansions of P to that of rod Q is:

• A. 2 : 5
• B. 5 : 2
• C. 1 : 1
• D. 4 : 1

Answer 1

The correct option is C 1 : 1

Linear expansion means change in one dimension (length) as opposed to change in volume (volumetric expansion). To a first approximation, the change in length measurements of an object due to thermal expansion is related to temperature change by a "linear expansion coefficient".

Since in this case the material lenght and heated to same temperature rise then the linear expansion in rod will be same.

Hence,the ratio of thermal expansion is $1:1$