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#barometer

5 public questions tagged with this topic.

A mercury barometer shows a height of 75 cm at sea level. What is the atmospheric pressure? ( rho = 13.6 × 10³kg/m³, g =

Given: A mercury barometer shows a height of 75 cm at sea level. What is the atmospheric pressure? ( rho = 13.6 × 10³kg/m³, g = 10 m/s² ) These values define the system as per NCERT data. Formula: P_a = rho g h. This is standard NCERT relation. Substitution & Calculation: rho = 13.6 × 10³kg/m³, g = 10 m/s², h = 0.75 m . P_a = 13.6 × 10³ × 10 × 0.75 = 1.02 × 10⁵Pa . Result: The computed value matches expected outcome and confirms correct choice as per NCERT.

Ref: NCERT Physics Textbook for Class XI and XII, Chapter: Relevant Physics topic covering fundamental principles,

Why does the height of a mercury column in a barometer decrease during a storm?

The barometer measures atmospheric pressure ( P_a = rho g h ). During a storm, atmospheric pressure drops, reducing the force supporting the mercury column, causing its height to decrease, as noted in the chapter.

Ref: NCERT Physics Textbook for Class XI and XII, Chapter: Laws of Motion, Work Energy Power, Gravitation and System of Particles, Topic: Newton's laws, work-energy theorem and rotational dynamics.