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- Question
A capillary tube is partially dipped vertically in a vessel containing water. Due to capillarity water rises in the tube. The height of water rise in the tube can be increased by
Options- A. decreasing the radius of the capillary tube
- B. increasing the radius of the capillary tube
- C. increasing the height of water in the vessel
- D. None of these
- Correct Answer
- decreasing the radius of the capillary tube
ExplanationThe water rise in a capillary tube dipped in water is such that the weight of water in the tube above the surface of water in the vessel is equal to the upward force due to surface tension. So it is clear that if the bore to the tube is decreased , the height of the water column in it must be greater.
- 1. Solids have definite shapes.This is because
Options- A. the forces of cohesion of the molecules within are very much less in them
- B. the forces of cohesion are very large
- C. the forces of adhesion are large
- D. the forces of adhesion are less Discuss
- 2. Frictional force acts in
Options- A. the same direction as the motion
- B. the opposite direction of the motion
- C. all the directions
- D. upward direction Discuss
- 3. What is the minimum velocity required for a rocket to overcome earth's gravity and travel into space?
Options- A. 18 km/sec
- B. 11.2 km/sec
- C. 21 km/sec
- D. 35 km/sec Discuss
- 4. What is unit of Astronomical distance ?
Options- A. light year
- B. angstrom
- C. weber
- D. lux Discuss
- 5. What is unit of Viscosity ?
Options- A. coulomb
- B. newton second per square meter
- C. watt per meter per degree celcius
- D. joule per kilogram per Kelvin Discuss
- 6. The fact that two large ships travelling on close parallel courses in the same direction tend to move towards each other can be explained by
Options- A. Bernoulli's principle
- B. Magnetic properties of the ship's material
- C. Newton's third law of motion
- D. Earth's gravitational force Discuss
- 7. The cover of a solar coker is made of glass because
Options- A. it absorbs sun's rays
- B. it reflects sun's rays
- C. it retains the heat inside by the green house effect
- D. it rediates heat better than metals Discuss
- 8. Tap water is placed in an open pad and allowed to evaporate. After some time the temperature of water
Options- A. increases to a great extent
- B. increases slightly
- C. decreases slightly
- D. decreases rapidly Discuss
- 9. Radio waves sent out by a radio stations are reflected by
Options- A. troposphere
- B. stratosphere
- C. mesosphere
- D. ionosphere Discuss
- 10. A series of fast moving still pictures can be made to appear as a moving picture because the eye
Options- A. can focus very rapidly as pictures change
- B. is quicker than the brain
- C. can see 2 images separated only if the interval betwen seeing them is more than one-tenth of a second
- D. can shut out some of the light Discuss
Physics problems
Search Results
Correct Answer: the forces of cohesion are very large
Explanation:
Cohesion refers to attraction between molecules of the same kind while adhesion refers to attraction between different kinds of molecules
Correct Answer: the opposite direction of the motion
Explanation:
It is to overcome this opposite frictional force , that we have to apply the needed force to make the body move
Correct Answer: 11.2 km/sec
Explanation:
This 11.2 km/s is also known as the escape velocity. It works out to roughly 25000miles per hour
Correct Answer: light year
Explanation:
angstrom is used to measure wave length,
weber is used to measure Magnetic flux,
lux is used to measure Intensity of illumination.
Correct Answer: newton second per square meter
Explanation:
coulomb is unit of Electric Charge,
watt per meter per degree celcius is unit of Thermal Conductivity,
joule per kilogram per Kelvin is unit of Specific Heat capacity.
Correct Answer: Bernoulli's principle
Explanation:
The rapid flow of air between the two moving ships causes a reducton of pressure (Bernoulli's principle) , so they (the ships) are drawn closer together
Correct Answer: it retains the heat inside by the green house effect
Explanation:
As the inside of the cooker is painted black, heat absorption is more producing heat waves of longer wavelength which cannot escape through glass and hence are trapped inside. Thus the food is cooked.
Correct Answer: decreases slightly
Explanation:
Evaporation causing cooling.Here the evaporation is less. Therefore cooling is less.
Correct Answer: ionosphere
Explanation:
This is a layer of atmosphere about 60 to 70 km above the earth and extends to about 400km. It contains ionised particles which can reflect radio waves making radio communication round the world possible.
Correct Answer: can see 2 images separated only if the interval betwen seeing them is more than one-tenth of a second
Explanation:
The eye can see images separately only if they are exhibited at an interval of more than 1/10 of a second. In the case of a movie, the still pictures come one after the other at less than this minimum interval. So we do not see them separately but only as a continuous moving picture.
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