- 1(current)
Q. No.| 1. | surface tension. |
| 2. | density. |
| 3. | angle of contact between the surface and the liquid. |
| 4. | viscosity. |
A liquid does not wet the solid surface if the angle of contact is:
1. equal to \(45^{\circ}\)
2. equal to \(60^{\circ}\)
3. greater then \(90^{\circ}\)
4. zero
1. \(2: 1\)
2. \(3: 5\)
3. \(5: 4\)
4. \(4: 7\)
1. surface tension
2. buoyancy
3. viscosity
4. None of these
A capillary tube of radius \(0.20\) mm is dipped vertically in the water. The height of the water column raised in the tube will be:
(Surface tension of water\(=0.075\) N/m and density of water \(=1000\) kg/m3. Take \(g=10\) m/s2 and contact angle \(0^\circ.\))
1. \(7.5\text{ cm}\)
2. \(6\text{ cm}\)
3. \(5\text{ cm}\)
4. \(3\text{ cm}\)
| 1. | In a lift moving upward with acceleration, height is less than \(h.\) |
| 2. | In a lift moving downward with acceleration, height is more than \(h.\) |
| 3. | On the surface of the moon with acceleration \( (\leq g),\) the height is more than \(h.\) |
| 4. | All of the above are correct. |
When a long glass capillary tube of radius \(0.015~\text{cm}\) is dipped in a liquid, the liquid rises to a height of \(15~\text{cm}\) within it. If the contact angle between the liquid and glass to close to \(0^\circ\), the surface tension of the liquid, in milliNewton m–1, is:\(\left[\rho_{\text {(liquid) }}=900 \mathrm{~kgm}^{-3}, \mathrm{~g}=10 \mathrm{~ms}^{-2}\right] \) (Give answer in closest integer).
1. \(200\)
2. \(101\)
3. \(402\)
4. \(325\)
The angle of contact at the interface of the water glass is \(0^{\circ},\) ethyl-alcohol glass is \(0^{\circ},\) mercury-glass is \(140^{\circ}\) and methyl iodide-glass is \(30^{\circ}.\) A glass capillary is put in a trough containing one of these four liquids is observed that the meniscus is convex. The liquid in the trough is:
1. water
2. ethyl alcohol
3. mercury
4. methyl iodide
If the surface tension of water is \(0.06\text{ N/m},\) then the capillary rise in a tube of diameter \(1\text{ mm}\) is (\(\theta=0^{\circ}\))
1. \(1.22\text{ cm}\)
2. \(2.44\text{ cm}\)
3. \(3.12\text{ cm}\)
4. \(3.86\text{ cm}\)
| 1. | \(\left({\dfrac{2T}{r}}\right)\cos\mathit{\theta}\) | 2. | \(\dfrac{T}{{r}\cos\mathit{\theta}}\) |
| 3. | \(\dfrac{2T}{{r}\cos\mathit{\theta}}\) | 4. | \(\left({\dfrac{4T}{r}}\right)\cos\mathit{\theta}\) |
- 1(current)
Q. No.
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