Question
Physics Question on mechanical properties of fluid
An open U-tube contains mercury. When 11.2cm of water is poured into one of the arms of the tube, how high does the mercury rise in the other arm form its initial level?
A
0.56 cm
B
1.35 cm
C
0.41 cm
D
2.32 cm
Answer
0.41 cm
Explanation
Solution
Key Idea : At the same level in the two limbs of a U-tube, pressure is same.
On pouring water on left side, mercury rises xcm (say) from its previous level in the right limb of U-tube creating a difference of levels of mercury by 2xcm. Equating pressures at A and B, we get
PA=PB
∴11.2×10−2×ρwater ×g=2x×ρmercury ×g
⇒11.2×10−2×1000kg/m3
=2x×13600×kg/m3
⇒x=2×1360011.2×10−2×1000m
=0.41cm