| 1. | the density of the liquid | 2. | the surface tension |
| 3. | the atmospheric pressure | 4. | gravity |
| Assertion (A): | Clothes containing oil or grease stains cannot be cleaned by water wash |
| Reason (R): | Because the angle of contact between the oil/grease and water is obtuse. |
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 3. | (A) is True but (R) is False. |
| 4. | (A) is False but (R) is True. |
If work \(W\) is done in blowing a bubble of radius \(R\) from a soap solution, then the work done in blowing a bubble of radius \(2R\) from the same solution is:
1. \(W/2\)
2. \(2W\)
3. \(4W\)
4. \(2\dfrac{1}{3}W\)
| 1. | \(\dfrac{2S}{r}\) | 2. | \(\dfrac{4S}{r}\) |
| 3. | \(\dfrac{S}{r}\) | 4. | \(\dfrac{S}{2r}\) |
The surface tension of a soap solution is \(2 \times 10^{-2}\) N/m. If a soap bubble with a radius of \(4\) cm is blown, the amount of work done is:
1. \(4\pi \times 10^{-6}~\text{J}\)
2. \(2.56\pi \times 10^{-4}~\text{J}\)
3. \(16\pi \times 10^{-5}~\text{J}\)
4. \(16\pi \times 10^{-6}~\text{J}\)
| Assertion (A): | Smaller drops of water resist deformation forces better than larger drops. |
| Reason (R): | Excess pressure inside the drop is inversely proportional to its radius. |
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 3. | (A) is True but (R) is False. |
| 4. | (A) is False but (R) is True. |