# Linear Expansion of Solid Numericals Class 8

The linear expansion of a solid is an increase in the length of a wire or a rod of a solid due to an increase in its temperature. In this post, we will study related formulas and solve a numerical problem based on this the linear expansion of a solid.

Formulas Used

Change in length ΔL= α L1 ΔT………………. (1)

final length L2 = L1 + α L1 ΔT
=>L2 = L1(1 + α ΔT) …………… (2)

α = coefficient of linear expansion of the solid substance
α = (L2 – L1) /(L1 ΔT) …………. (3)

Numericals on Linear Expansion of Solid Class 8

Question: What will be the increase in length of a steel rod of length 0.5 m, when its temperature is increased by 60 0C? The coefficient of linear expansion of steel is 0.000013 (1/0C).

Solution:

Given : Initial length of the rod = 0.5 m, change in temperature = 60 0C,
change in length = ΔL = ?

Using formula ΔL= α L1 ΔT = = 0.000013 x 0.5 x 60 = 0.00039 m

Increase in length = 0.039 cm

See also  0.5 kg of lemon squash at 30 C is placed in a refrigerator which can remove heat at an average rate of 30 J s-1. How long will it take to cool the lemon squash to 5 C?
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