A barometer with a brass scale correct at 0°C reads 70 cm of mercury on a day when the air temperature is 40°C. the correct reading at 0°C is (Coefficient of real expansion of mercury is 0.00018/°C and the coefficient of linear expansion of brass is 0.000018/°C.

see full answer

Talk to JEE/NEET 2025 Toppers - Learn What Actually Works!

Real Strategies. Real People. Real Success Stories - Just 1 call away

An Intiative by Sri Chaitanya

20.5cm

69.5cm

60.5cm

50.00cm

answer is B.

(Unlock A.I Detailed Solution for FREE)

Ready to Test Your Skills?

Check your Performance Today with our Free Mock Test used by Toppers!

Take Free Test

Detailed Solution

t = 40°C; H = 70 cm of Hg; H₀ =?
$γ$ = 0.00018 = 180 x 10^-6/^oC
$α$ = 0.000018 = 18 x 10^-6/^oC
we have H₀ = H[1- ( $γ - α$ )t]
= 70[1 - (180 x 10^-6 - 18 x 10^-6)(40)]
= 69.5 cm of Hg

Result Producing online coaching for JEE/NEET of south India

Largest All India Test Series for JEE/NEET

Best Books for IIT JEE

Best Books for NEET

How to Join IIT after 10th

Best Courses for You

JEE

NEET

Foundation JEE

Foundation NEET

CBSE

Get Expert Academic Guidance – Connect with a Counselor Today!

Result Producing online coaching for JEE/NEET of south India

Largest All India Test Series for JEE/NEET

Best Books for IIT JEE

Best Books for NEET

How to Join IIT after 10th