Question

B. Statements given below are incorrect. Write
the correct statements :
1. The increase in area of a solid when heated,
is called cubical expansion. linear
2. On heating, the bimetallic strip (brass and
iron) bends in such a way that the brass is
on the inner side while iron is on outer side
of the bend.
3. To avoid derailment of train, the rails are
fixed tightly, leaving no space for expansion
or contraction.
4. The girders supporting the bridge are fixed
in the walls of the pillars.
5. The metallic wires contract during summer
and can break.
C​

Answer 1

Answer:

1. Whenever there is an increase in the length of a

body due to heating then the expansion is called linear

2. When a bimetallic strip of brass-iron is heated,the brass expands more than the iron. Explanation.

3. rails are fixed tightly, leaving no space for expansion or contraction, these will bend outward in summer.

4. One end of the girders is fixed into the concrete or brick pillars and its other end is not fixed , but is placed on rollers.

5. Metals expand on heating in summer and contract on cooling in winter.

Answer 2

Answer$:

1) The increase in area of a solid when heated, is called superficial expansion.

2) On heating, the bimetallic strip (brass and iron) bends in such a way that the brass is on the outer side while iron is on inner side of the bend.

3) To avoid derailment of train, the rails are not fixed tightly, leaving space for expansion or contraction.

4) The girders supporting the bridge are not fixed in the walls of the pillars.

5) The metallic wires expand during summer and can break.