Question

2.
The length of a metal rod at 15 °C is 50 cm
and at 90 °C, it is 50.15 cm. The coefficient of
linear expansion of the material of rod is
(A) 4x 10-6C (B) 2.4 x 10+ 0
(C) 4.2 x 10-4-C D 4x109,C​

Answer 1

Explanation:

α=

L

1

△T

△L

(1)

L

1

=50cm

L

2

=50.06cm

△L=0.06cm

T

1

=20℃

T

2

=95℃

△T=75℃

Putting value in (1) to find coefficient of Linear expansion

α=

(50)(75)

0.06

α=16×10

−6

℃

−1

Now, temperature at 0

o

C

Length at 0

o

C=L

3

L

3

=L

2

(1+α△T)

△T=0−20℃

△T=−20℃

L

3

=50[1+16×10

−6

×(−20)]

L

3

=49.984cm