Question

THERMAL EXPANSION
Passage-1:X
its temperature is raised from 0°C to 50°C.
10
d) 4:3
a) 2:1
b) 3:2
c) 3:1
TO
d) 40 cm
c) 30 cm
18
8
a) 10 cm
b) 20 cm
The length of the rod of metal Y in the composite piece is
a) 10 cm
b) 20 cm
d) 40 cm
c) 30 cm
CONCEPT - III
Relation between Coefficients of expansion OF SOLIDS:
Consider a cube of unit length made of Isotropic material. It is heated through 1°C raise of temp
Before Heating
Initial length of the cubel, = Im
Initial area of the cube A = = I x1 = 1m
A rod of metal X of length 50.0 cm elogates by 0.10 cm when it is heated from 0°C to 100 C. An
length 50 cm, made by welding pieces of rods X and Y placed end to end. elongates by 0.03 cm
rod of metal Y of length 80.0 cm elongates by 0.08 cm for the same rise in temperautre. A third
The coefficients of linear expansion of metal X and of metal Y are in the ratio of
The length of the rod of metal X in the composite piece is​

Answer 1

Explanation:

since the difference in length for both the rods are same always, we can write,

α

1

l

1

=α

2

l

2

l

1

/l

2

=α

2

/α

1

or, (l

1

−l

2

)/l

2

=(α

2

−α

1

)/α

1

= 0.55/1.1 = 1/2

(l

1

−l

2

) = 10 (given)

Calculating we ge l

1

= 30 cm . So, l

2

= 20 cm