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Standard XII

Physics

Atmospheric Pressure

The brass sca...

Question

The brass scale of a barometer gives correct reading at $0^{o} C$ . The barometer reads $75 c m$ at $27^{o} C$ . what is the correct atmospheric pressure at $27^{o} C$ . Tne coefficient of linear expansion $α$ of brass is $2.0 \times 10^{- 5}$ degree/celcius

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Solution

$L_{o}$ = 75cm

α = $\frac{20 \times 10^{- 6}}{d e g r e e - c e l c i u s}$

$Δ T$ = 27 – 0 = 27 degree-celsius

L = ?

# Formula-

We'll use the formula for the coefficient of linear expansion

$L = L_{o} (1 + a Δ T)$

$L = 75 (1 + 20 \times 10^{- 6} \times 27)$

$L = 75 (1 + 0.00054)$

$L = 75 \times 1.00054$

$L = 75.0405 c m$

Atmospheric pressure at
$27^{0}$ is $75.0405$ cm of brass.

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The brass scale of a barometer gives correct reading at 0oC. The barometer reads 75cm at 27oC. what is the correct atmospheric pressure at 27oC. Tne coefficient of linear expansion α of brass is 2.0×10−5degree/celcius

Lo = 75cmα = 20×10−6degree−celciusΔT= 27 – 0 = 27 degree-celsiusL = ?# Formula-We'll use the formula for the coefficient of linear expansionL=Lo(1+aΔT)L=75(1+20×10−6×27)L=75(1+0.00054)L=75×1.00054L=75.0405cmAtmospheric pressure at 270 is 75.0405 cm of brass.

The brass scale of a barometer gives correct reading at $0^{o} C$ . The barometer reads $75 c m$ at $27^{o} C$ . what is the correct atmospheric pressure at $27^{o} C$ . Tne coefficient of linear expansion $α$ of brass is $2.0 \times 10^{- 5}$ degree/celcius