Three liquids of densities \(\rho_1,\rho_2\) and \(\rho_3\) \((\rho_1>\rho_2>\rho_3)\) having the same value of surface tension \(T\), rise to the same height in three identical capillaries. The angles of contact \(\theta_1\), \(\theta_2\), and \(\theta_3\) obey:
1. \( \frac{\pi}{2}>\theta_1>\theta_2>\theta_3 \geq 0 \)
2. \( 0 \leq \theta_1<\theta_2<\theta_3<\frac{\pi}{2} \)
3. \( \frac{\pi}{2}<\theta_1<\theta_2<\theta_3<\pi \)
4. \( \pi>\theta_1>\theta_2>\theta_3>\frac{\pi}{2} \)
A capillary tube of radius \(r\) is immersed in water and water rises in it to a height \(h.\) The mass of the water in the capillary is \(5\) g. Another capillary tube of radius \(2r\) is immersed in water. The mass of water that will rise in this tube is:
1. | \(5.0\) g | 2. | \(10.0\) g |
3. | \(20.0\) g | 4. | \(2.5\) g |
When a capillary tube is dipped into a liquid, the liquid neither rises nor falls in the capillary.
a. | the surface tension of the liquid must be zero. |
b. | the contact angle must be \(90^\circ.\) |
c. | the surface tension may be zero. |
d. | the contact angle may be \(90^\circ.\) |
Choose the correct option:
1. | (a) and (b) |
2. | (b) and (c) |
3. | (c) and (d) |
4. | all of these |