Physics · JEE | THERMAL PROPERTIES OF MATTER

A solid rectangular sheet of dimensions \( a \) and \( b \) undergoes area expansion when heated by \( \Delta T \). The fractional change in area \( \Delta A / A \) is equal to:

1. A
   \( \alpha_l \Delta T \)
2. B
   \( 2\alpha_l \Delta T \)
3. C
   \( 3\alpha_l \Delta T \)
4. D
   \( 4\alpha_l \Delta T \)