Question

A mercury pallet is trapped in a horizontal tube of small cross–section area. Length of tube enclosed by mercury pallet is 20 cm when it is accelerated with a = g/2 in the direction shown. The length of tube enclosed by pallet if it is accelerated in opposite direction with same acceleration is : (Atmospheric pressure is 7.2.5 cm of Hg)

• A. 22 cm
• B. 22.5 cm
• C. 21 cm
• D. 21.4 cm

Answer 1

Answer: (D)

21.4 cm

Answer 2

P₁ = P₀ +$\frac{a}{g}$.l

= 72.5 + 2.5 = 75 cm of Hg

P₂ = 72.5 – 2.5 = 70 cm of Hg

P₂ x₂ = P₁x₁ Ž x₂ = $\frac{75 \times 20}{70}$= 21.42 cm