Question

Coefficient of linear expansion of brass and steel rods are a1 and a2. Lengths of brass and steel rods are l1 and l2 respectively. If (l2-l1) is maintained same at all temperature, which one of the following relations holds good ?
(a). a1^2l2= a2^2l1
(b). a1l1=a2l2
(c). a1l2=a2l1
(d). a1l2^2=a2l1^2​

Answer 1

Answer:

b) a1l1=a2l2

Explanation:

If the difference between the two rods are same at all temperatures

then,

l2-l1=l'2-l'1

{ say, the lengths of the rods at t2

temperature are l'1 and l'2 respectively}

or ,l'2-l2= l'1-l1

or, l2×a2×t =l1×a1×t

a1l1=a2l2 (Ans)