Question

(6)* A bridge is made from 20 m long iron rods. At temperature 18 °C, the distance between two rods
is 0.4 cm. Up to what temperature will the bridge be in good shape?
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Answer 1

Answer:

Length of the iron rod = 20 m = 2000 cm at 18°C

Distance between the length of two rods = 0.4 cm

Temperature coefficient of linear expansion of iron = 11.5 × 10−6 °C−1

The bridge will be in proper and good shape until both the rods expand by 0.2 cm due to increase in temperature. Let the temperature be T, both the rods expand by 0.2 cm i.e. the total expansion of rods is 0.4 cm.

Using formula for linear expansion of solids, we have

∆l / l = α1∆T

⇒0.4 / 2000 = 11.5 × 10−⁶ × (T−16)

T = 18 + 0.4 /2000 × 11.5 × 10-⁶ = 35.4°C

Answer 2

Refer to the attachment for the answer :)

thanks