Question

Barometer reads 74 cm on a steel scale, the room temperature is 25oc25oc. The scale is correctly graduated for 0oc0oc. Find the true atmospheric pressure. Αsteel=1.2×10−5/ocαsteel=1.2×10−5/oc, γhg=1.8×10−4/oc

Answer 1

Use formula of thermal expansion ,

∆L = L₀α∆T

where ∆L is the change in length of object after changing temperature

L₀ is the initial length of object

∆T is the temperature change

and α is the coefficient of linear expansion

Here, ∆L = 6 × 10⁻⁵ mm = 6 × 10⁻⁸ m

L₀ = 1mm = 10⁻³ m

α = 12 × 10⁻⁶ /K

Now, 6 × 10⁻⁸ = 10⁻³ × 12 × 10⁻⁶ ∆T

60 = 12∆T ⇒ ∆T = 5K or 5 /°C

Hope this helps you ☺️☺️❤️❤️✌️✌️

Answer 2

oops not understandable