Strips of two metals A and B are firmly joined together as shown in the figure. On heating, A expands more than B does. If this joined strip is heated, then it will appear as:

1. The question describes a bimetallic strip made of two metals, A and B, firmly joined. Metal A expands more than metal B upon heating. 2. When a bimetallic strip is heated, the metal with the higher coefficient of thermal expansion (metal A in this case) will expand more in length. 3. Since the two strips are firmly joined, this differential expansion forces the strip to bend. 4. The side with the higher expansion (metal A) will form the outer curve (longer radius) because it needs more length, while the side with lower expansion (metal B) will form the inner curve (shorter radius). 5. The figure shows the initial state with A on top and B below. Upon heating, A expands more, so it must be on the outside of the bend. This means the strip will bend downwards, with A forming the convex (outer) side and B forming the concave (inner) side. 6. Option (b) in the figure depicts this scenario where the strip bends downwards with A on the outer (top) curve.