Question

Select One Option Correct from the following : A glass capillary tube is of the shape of a truncated cone with an apex angle $\alpha$ so that its two ends have cross sections of different radii. When dipped in water vertically, water rises in it to a height h, where the radius of its cross-section is b. If the surface tension of water is S, its density is $\rho$, and its contact angle with glass is $\theta$, the value of h will be (where g is acceleration due to gravity)
(A)$\frac{2S}{b\rho g} \cos(\theta - \alpha)$
(B)$\frac{2S}{b\rho g} \cos(\theta + \alpha)$
(C)$\frac{2S}{b\rho g} \cos(\theta - \alpha/2)$
(D)$\frac{2S}{b\rho g} \cos(\theta + \alpha/2)$

Answer 1

Select One Option Correct from the following : A glass capillary tube is of the shape of a truncated cone with an apex angle $\alpha$ so that its two ends have cross sections of different radii. When dipped in water vertically, water rises in it to a height h, where the radius of its cross-section is b. If the surface tension of water is S, its density is $\rho$, and its contact angle with glass is $\theta$, the value of h will be (where g is acceleration due to gravity)

✔️(A)$\frac{2S}{b\rho g} \cos(\theta - \alpha)$

(B)$\frac{2S}{b\rho g} \cos(\theta + \alpha)$

(C)$\frac{2S}{b\rho g} \cos(\theta - \alpha/2)$

(D)$\frac{2S}{b\rho g} \cos(\theta + \alpha/2)$