Question

The ratio of lengths of two rods of different materials is taken as 2 : 3 such that the difference of their lengths is 10 cm at all temperatures. The length of the rod of lesser expansion is a x 10 cm. The value of a 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