InterviewSolution
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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 151. |
The surface tension of liuid at its boiling pointA. is zeroB. is infiniteC. is same as that of any other temperatureD. canot be determined |
| Answer» Correct Answer - A | |
| 152. |
A drop of oil is placed on the surface of water. Which of the following statements is correctA. it will remain on it as a sphereB. it will pread as a thin layerC. it will partly be a spherical droplet and partly a thin filmD. it will float as a distorted drop on the water surface |
| Answer» Correct Answer - B | |
| 153. |
If two glass plates are quite nearer to each other in water, then there will be force ofA. AttractionB. RepulsionC. Attraction or repulsionD. none of these |
| Answer» Correct Answer - A | |
| 154. |
The property of surface tension is obtained inA. Solids, liquids and gasesB. LiquidsC. gasesD. Matter |
| Answer» Correct Answer - B | |
| 155. |
The surface of a liquid has tendency to contract and minimise surface area . This tendency is due toA. viscosityB. elasticityC. frictionD. surface tension |
| Answer» Correct Answer - D | |
| 156. |
The surface tension of a liquid ____ with rise of temperature.A. increase with areaB. Decreases with areaC. Increase with temperatureD. Decrease with temperature |
| Answer» Correct Answer - D | |
| 157. |
When soap solution dissolves in water , then the surface tension of soap solution isA. reducedB. increasedC. remains constantD. zero |
| Answer» Correct Answer - A | |
| 158. |
The surface tension of a liquid ____ with rise of temperature.A. decreasesB. increasesC. remains sameD. independent of temperature |
| Answer» Correct Answer - A | |
| 159. |
Surface tension is due toA. adhesive forceB. gravitational forceC. cohesive forceD. electrostatic force |
| Answer» Correct Answer - C | |
| 160. |
The angle of contact for pure water and clean glass surface isA. zeroB. `90^(@)`C. `15^(@)`D. `137^(@)` |
| Answer» Correct Answer - A | |
| 161. |
The work done to increase unit area of the liquid surface is equivalent toA. surface energyB. surface tensionC. work doneD. energy stored |
| Answer» Correct Answer - B | |
| 162. |
The surface of water in contact with glass wall isA. concaveB. convexC. planeD. horizontal |
| Answer» Correct Answer - A | |
| 163. |
When the temperature increased the angle of contact of a liquidA. IncreasesB. DecreasesC. Remains the sameD. First increases and then decreases |
| Answer» Correct Answer - B | |
| 164. |
Surface tension of water is 0.07 N/m . The weight of water supported by the surface tension in a capillary tube of radius ` 1 xx 10^(-4)` m will beA. `440 xx 10^(-6)` NB. ` 44 xx 10^(-6)`NC. ` 4.4 xx 10^(-6) N`D. ` 0.44 xx 1-0^(-6)`N |
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Answer» Correct Answer - B `T = F/l :. F = Trho ` ` F = 7 xx 10^(-2) xx 2 pi r ` ` 7 xx 10^(-2) xx 2xx 22/7 xx 10^(-4) ` ` = 44 xx10^(-6) ` N |
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| 165. |
Alcohol of density ` 8 xx 10^(4) kg//m^(3)` and surface tension ` 22 xx 10^(-3)` N/m rises through a capillary tube of diameter ` 0.4 xx 10^(-3)` m . The vertical height to which the alcohol will rise is ,A. `28 xx 10^(-4)`,mB. `2.8 xx10^(-4)`C. `0.28xx10^(-4)`mD. `0.28xx10^(-4)`m |
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Answer» Correct Answer - B ` h = (2T cos theta )/(rho gr)` ` = (2xx22xx10^(-3)xx1)/(8 xx10^(+4)xx10xx2xx10^(-4))= 2.8 xx10^(-4)` m |
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| 166. |
What will happen to the motor bike, if some water is poured in its machinery parts?A. Machinery parts are jammed due to increase in surface tensionB. Machinery parts are jammed due to decrease in surface tensionC. Machinery parts are jammed due to decrease calorific valueD. nothing will happen |
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Answer» Correct Answer - A Due to the presence of water the surface tension of lubricating oil increases so, machinery parts jammed. |
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| 167. |
A rectangular film of liquid is extended from `5 cm xx 3 cm to 6 cm xx 5 cm`. If the work done is `3.0 xx 10^(-4) J`. The surface tension of liquid isA. `0.5 Nm^(-1)`B. `0.1 Nm^(-1)`C. `0.2 Nm^(-1)`D. `2 Nm^(-1)` |
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Answer» Correct Answer - B Given, `A_(1) = 5 cm xx 3 cm = 15 cm^(2)` `A_(2) = 6 cm xx 5 cm = 30 cm^(2)` `W = 3.0 xx 10^(-4) J` `S = ?` Increase in area, `Delta A = 2(6 xx 5-5 xx 3) = 2 xx 15 cm^(2)` [film has 2 free surfaces] `= 30 xx 10^(-4) m^(2)` As work done , W = surface tension `xx` increase in area `3.0 xx 10^(-4) = S xx 30 xx 10^(-4)` `rArr S = 0.1 Nm^(-1)` |
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| 168. |
A mass of metal is molded into solids of different shapes . Its surface area is the least when it isA. a sphereB. a right circular cylinderC. a paraboloidD. a right circular cone |
| Answer» Correct Answer - C | |
| 169. |
Coating used on raincoat are waterproof becauseA. Water is absorbed by the coatingB. cohesive force becomes greaterC. Water is not scattered away by the coatingD. Angle of contact decreass |
| Answer» Correct Answer - B | |
| 170. |
It is difficult to write legibly on a news paper because ofA. capillarityB. viscosityC. surface tensionD. inhertia |
| Answer» Correct Answer - A | |
| 171. |
The reason of capillarity is due toA. surface tension forceB. viscus forceC. gravitational forceD. capillary action |
| Answer» Correct Answer - D | |
| 172. |
When there are no external forces, shape of the liquid is determined byA. surface tension of the liquidB. density of the liquidC. viscosity of airD. temperature of air |
| Answer» Correct Answer - A | |
| 173. |
A tapering glass capillary tube A of length `0.1 m` has diameters `10^(-3)` m and `5 × 10^(4)` m at the ends. When it is just immersed in a liquid at `0^(@)`C with larger radius in contact with liquid surface, the liquid rises `8 × 10^(-2)` m in the tube. In another experiment, in a cylindrical glass capillary tube B, when immersed in the same liquid at `0^(@)`C, the liquid rises to `6 × 10^(-2)` m height. The rise of liquid in tube B is only `5.5 × 10^(-2)` m when the liquid is at `50^(@)`C. Find the rate at which the surface tension changes with temperature considering the change to be linear. The density of liquid is `(1//14) × 10^(4) kg//m^(3)` and the angle of contact is zero. Effect of temperature on the density of liquid and glass is negligible. |
| Answer» Correct Answer - `-1.4 xx 10^(-4)N//(m-.^(0)C)` | |
| 174. |
A glass `U-`tube is inverted with open ends of the straight limbs, of diameters `0.5 mm` and `1.0 mm` below the surface of water in a beaker. The air pressure in the upper part is increased until the meniscus in one limb is level with the water outside. Find the height `(cm)` of water in the other limb in nearest integer. : (Density of water is `10^(3)Kg//m^(3)` and surface tension of water is `7.5 xx 10^(-2)N//m`. Take contact angle `theta = 0^(@)`) |
| Answer» Correct Answer - `3` | |
| 175. |
A glass plate of length `0.1 m`, breadth `15 xx 10^(3) m` and thickness `2 xx 10^(-3)m` weighs `8 xx 10^(-3) kg` in air, it is held vertically with its longer side horizontal and its lower half immersed in water. If the surfaces tension of water is `72 xx 10^(-3) N//m`, the apparent weight of the plate is `79.4 lambda xx 10^(-3) N`. Then find `lambda` |
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Answer» Correct Answer - `1` `w_(app) = mg - f_(B) + 2T (l + T) = 8 xx 10^(-3) xx 10 - (0.1 xx 15 xx 10^(-3) xx 2 xx 10^(-3) )/(2) xx 10^(3) xx 10 + 2 xx 72 xx 10^(-3) (0.1 + 2 xx 10^(-3))= 79.4 xx 10^(-3) N` |
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| 176. |
The excess pressure inside a soap bubble of diameter 2 cm of soap solution of surface tensionA. `100 N//m^(2)`B. `10 N//m^(2)`C. `1 N//m^(2)`D. `0.1 N//m^(2)` |
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Answer» Correct Answer - B ` (4T)/R = Delta P, (4 xx 25 xx 10^(-3)N//m)/(1xx 10^(-2)m)` ` = 100 xx 10^(-3) xx10^(2) " N/m"^(2)` ` = 10 " N/m"^(2)` |
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| 177. |
Surface tension may be defined asA. The work done per unit area in increasing the surface area of a liquid under isothermal conditionB. The work done per unit area in increasing the surface area of a liquid under adiabatic conditionC. The work done per unit area in increasing the surface area of a liquid under both isothermal and adiabatic conditionsD. Free surface energy per unit volume |
| Answer» Correct Answer - A | |
| 178. |
The force required to take away a flat circular plate of radius 2 cm from the surface of water, will be (the surface tension of water is 70 dyne/cm)A. `280 pi`dyneB. `250 pi `dyneC. `140 pi` dyneD. 210 pi `dyne |
| Answer» Correct Answer - A | |
| 179. |
A circular ring has inner and outer radii equal to `10 mm and 30 mm` respectively Mass of the ring is `m = 0.7` g. It gently pulled out vertically from a water surface by a sensitive spring. When the spring is stretched `3.4 cm` from its equilibrium position the ring is on verge of being pulled out from the water surface. If spring constant is `k = 0.7 Nm^(–1)` find the surface tension of water. |
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Answer» Correct Answer - `0.076Nm^(-1)` |
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| 180. |
The molecular forces areA. short range forcesB. intermediate forcesC. long range forcesD. multi range forces |
| Answer» Correct Answer - A | |
| 181. |
The surface tension of water at freezing point isA. zeroB. infinityC. same as that of beforeD. any values from zero to infinity |
| Answer» Correct Answer - A | |
| 182. |
What make it difficult to separate two glass sheets having a drop of water between them .A. viscosityB. gravityC. surface tensionD. atmospheric pressure |
| Answer» Correct Answer - C | |
| 183. |
When a small quantity of soluable impurity is added to water , then its surface tensionA. increasesB. decreasesC. may increase or decrease depending upon impurityD. remains same |
| Answer» Correct Answer - A | |
| 184. |
When sugar is added to water , then surface tension of sugar solution isA. less then that of waterB. same as that of waterC. more that of waterD. some times more and sometimes less than that of water |
| Answer» Correct Answer - C | |
| 185. |
If there is no difference of pressure on the two sides of the surface, then the liquid surface isA. concaveB. convexC. cylindricalD. plane |
| Answer» Correct Answer - D | |
| 186. |
If the surface tension of a rectangular soap film is T and length l , total force acting on it is ,A. 2T/lB. l/2TC. T/2lD. 2 Tl |
| Answer» Correct Answer - D | |
| 187. |
If two soap bubble of different radii are in communication with each otherA. air flows from the larger bubble into smaller bubble until they have the same sizeB. the size of the bubbles remains the sameC. air flows from smaller bubble into larger bubble and the larger size of the smaller bubble decreasesD. air may flow from the smaller into the larger or from the larger into smaller depending upon the concentration of the soap solution . |
| Answer» Correct Answer - C | |
| 188. |
A narrow tube of length `l` and radius `r` is sealed at one end. Its open end is brought in contact with the surface of water while the tube is held vertical. The water rises to a height `h` in the tube. The contact angle of water with the tube wall is `theta`, density of water is `rho` and the atmospheric pressure is `P_(o)`. Find the surface tension of the liquid. Assume that the temperature of air inside the tube remains constant and the volume of the meniscus is negligible. |
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Answer» Correct Answer - `T=r/(2cos theta)[(P_(o)h)/(l-h)+rhogh]` |
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| 189. |
The limbs of a manometer consists of uniform capillary tubes of radii `1.44 xx 10^(-3)m` and `7.2 xx 10^(4 )m`. If the level of the liquid in the narrower tube stands 0.2 m above that in the broader tube, pressure difference between A and B is found to be `310lambda N//m^(2)`. Here `lambda` is an integer. Find `lambda` (density = `10^3 kg//m^3`, surface tension = `72 xx 10^(-3) N//m`). (take `g = 9.8 m//s^2`) |
| Answer» Correct Answer - `1860 N//m^(2)` | |
| 190. |
Two small drop of mercury, each of radius R coalesce in from a simple large drop. The ratio of the total surface energies before and after the change isA. `1:2^(1//3)`B. `2^(1//3) :1`C. `2:1`D. `1:2` |
| Answer» Correct Answer - B | |
| 191. |
Which graph represents the variation of surface tension with temperature over small temperature ranges for water?A. B. C. D. |
| Answer» Correct Answer - B | |
| 192. |
It becomes easier to spray the water in which some soap is dissolved. Why?A. If both assertion and reason are true and the reason is the correct explanation of the assertion.B. If both assertion and reason are true but reason is not the correct explanation of the assertion.C. If assertion is true but reason is falseD. If the assertion and reason both are false |
| Answer» Correct Answer - C | |
| 193. |
In the following questions, a statement of assertion is followed by a statement of reason. Mark the correct choice as (a) If both assertion and reason are true and reason is the correct explanation of assertion. (b) If both assertion and reason are true but reason is not the correct explanation of assertion. (c ) If assertion is true but reason is false. (d) If assertion and reason are false. Q. Assertion: When height of a tube is less than liquid rise in the capillary tube, the liquid does not overflow. Reason: Product of radius of meniscus and height of liquid in capullary tube always remains constant.A. If both assertion and reason are true and the reason is the correct explanation of the assertion.B. If both assertion and reason are true but reason is not the correct explanation of the assertion.C. If assertion is true but reason is falseD. If the assertion and reason both are false |
| Answer» Correct Answer - A | |
| 194. |
It is better to wash the clothes in hot soap solution. Why?A. Surface tension is moreB. Surface tension is lessC. Consumes less soapD. None of these |
| Answer» Correct Answer - B | |
| 195. |
Statement-1: It is better to wash the clothes in cold soap solution. Statement-2: The surface tension of cold solution is more than the surface tension of hot solution:A. If both assertion and reason are true and the reason is the correct explanation of the assertion.B. If both assertion and reason are true but reason is not the correct explanation of the assertion.C. If assertion is true but reason is falseD. If assertion is false but reason is true. |
| Answer» Correct Answer - D | |
| 196. |
Water rises to height of 5 cm in glass capillary tube . If the area of cross section of the tube is reduced to `((1)/(16))` th of the former value , the water rises to a height ofA. 20 cmB. 30 cmC. 80 cmD. 40 cm |
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Answer» Correct Answer - A ` A_(2)=1/4A_(1)` `pir_(2)^(2)=1/4A_(1)pir_(1)^(2)` ` r_(2) = (r_(1))/2` `h_(2)r_(2)= h_(1)r_(1)` `h_(2)=4xx2 = 8` |
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| 197. |
Soap helps in cleaning clothes, becauseA. Chemical s of soap changeB. it increase the surface tension of the solutionC. It absorbs the dirtD. it lowers the surface tension of the solution |
| Answer» Correct Answer - D | |
| 198. |
A spherical drop of water has `1mm` radius. If the surface tension of the water is `50 xx 10^(-3) N//m` then find the difference of pressure between inside and outside the spherical drop is : |
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Answer» Correct Answer - `100N/m^(2)` `P_(excess) = (2T)/(R) = (2(50 xx 10^(-3)))/(10^(-3)) = 100 N//m^(2)` |
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| 199. |
Statement I: Smaller drops of liquid resist deforming forces better than the larger drops. Statement II: Excess pressure inside a drop is directly proportional to its surface area.A. If both assertion and reason are true and the reason is the correct explanation of the assertion.B. If both assertion and reason are true but reason is not the correct explanation of the assertion.C. If assertion is true but reason is falseD. If the assertion and reason both are false |
| Answer» Correct Answer - B | |
| 200. |
A rectagular wire frame with one movable side is convered by a soap film (fig.). What work `(erg)` will be done if this side of the frame is moved a distance `S = 2 mm` ? The length of the movable side is `l = 6cm`. The surface tension of the soap film is `alpha = 40 "dyne"//"cm"`. |
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Answer» Correct Answer - `96` `F = 2Tl = 2 xx 40 xx 6 = 480 "dyne"` `W = F xx = 480 xx 0.2 = 96 erg` |
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