When a glass capillary tube of the radius 0.015 cm is dipped in water, the water rises to a height of 15 cm within it. Assuming the contact angle between water and glass to be 0° , the surface tension of water is [.ρ textwater =1000 kg m- 3, g=9.81 ms- 2].

Question

When a glass capillary tube of the radius 0.015 cm is dipped in water, the water rises to a height of 15 cm within it. Assuming the contact angle between water and glass to be 0° , the surface tension of water is [.ρ textwater =1000 kg m- 3, g=9.81 ms- 2]. (A) 0.11 N m- 1 (B) 0.7 N m- 1 (C) 0.072 N m- 1 (D) None of these

Tardigrade Admin · Accepted Answer

From capillary tube experiment, we know that 2π r× T cosθ =π r2hρ g ⇒ T=(r h ρ g/2)=0.11 N m- 1

Q. When a glass capillary tube of the radius $0.015 c m$ is dipped in water, the water rises to a height of $15 c m$ within it. Assuming the contact angle between water and glass to be $0^{\circ}$ , the surface tension of water is $[ρ_{water} = 1000 k g m^{- 3}, g = 9.81 m s^{- 2}]$

$0.11 N m^{- 1}$

$0.7 N m^{- 1}$

$0.072 N m^{- 1}$

None of these

From capillary tube experiment, we know that
$2 π r \times T cos θ = π r^{2} h ρ g$
$\Rightarrow T = \frac{r h ρ g}{2} = 0.11 N m^{- 1}$

Q. When a glass capillary tube of the radius 0.015cm is dipped in water, the water rises to a height of 15cm within it. Assuming the contact angle between water and glass to be 0∘ , the surface tension of water is [ρwater ​=1000kgm−3,g=9.81ms−2]

0.11Nm−1

0.7Nm−1

0.072Nm−1