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Practice MCQ Questions and answers on Physics-GK

Learn and practice General Knowledge questions and answers on Physics with very easy and understandable explanations. GK questions are very helpful different type of competitive exams. Page-8 section-9

Each section contains 100 MCQs on Physics .
71
Which of these liquids has the highest viscosity?
Discuss
Answer & Solution
Answer: Option B
Solution:
Syrup has the highest viscosity.
72
The absorption of ink by blotting paper involves
Discuss
Answer & Solution
Answer: Option C
Solution:
The absorption of ink by blotting paper involves capillary action phenomenon because the blotting paper is a thin and a smooth paper which allows a little thicker liquids like ink to absorb.
73
Water from soil enters into the root hairs owing to :
Discuss
Answer & Solution
Answer: Option B
Solution:
In plants, the transpiration stream is the uninterrupted stream of water, and other, which is taken up by the roots and, via the xylem vessels, transported to the leaves where it will eventually evaporate into the air/apoplast-interface of the substomatal cavity. It is driven in by capillary action and in some plants root pressure. The main driving factor is the difference in water potential between the soil and the substomatal cavity caused by transpiration.
74
Which of the following liquids has the least density ?
Discuss
Answer & Solution
Answer: Option C
Solution:
Gasoline or petrol is a transparent, petroleum derived liquid that is used primarily as a fuel in internal combustion engines. It consists mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with a variety of additives. The specific gravity (or relative density) of gasoline ranges from 0.71–0.77 kg/l (719.7 kg/m3 ; 0.026 lb/m3; 6.073 lb/US gal; 7.29 lb/imp gal), higher densities having a greater volume of aromatics. Gasoline floats on water; water cannot generally be used to extinguish a gasoline fire, unless used in a fine mist.
75
A small drop of oil spreads over water because :
Discuss
Answer & Solution
Answer: Option B
Solution:
Surface tension of oil is smaller than that of water. When oil is dropped on the surface of water, the force stretches the oil drops on all sides. Hence the oil spreads over the surface of water.
76
Two rods, one of copper and other of steel, experience the same upthrust when placed in water.Thus, both have
Discuss
Answer & Solution
Answer: Option A
Solution:
When a body is placed in water, the upthrust or buoyant force acting on it depends upon the following factors: (i) Volume of the body submerged in the liquid - (V), or volume of the liquid displaced - (V); (ii) Density of the liquid - (d); and (iii) Acceleration due to gravity In-line. Since in the present question, we can assume g to be a constant and know that steel and copper have different densities, the only case in which they can have similar upthrust will be because of their volumes.
77
If ice floating on water in a vessel melts, the water level in the vessel ________ .
Discuss
Answer & Solution
Answer: Option B
Solution:
If ice floating on water in a vessel melts, the water level in the vessel does not change.
78
On a clean glass plate a drop of water spreads to form a thin layer whereas a drop of mercury remains almost spherical because
Discuss
Answer & Solution
Answer: Option C
Solution:
On a clean glass plate a drop of water spreads to form a thin layer whereas a drop of mercury remains almost spherical because cohesion of mercury is greater than its adhesion with glass.
79
The velocity of falling rain drops attains a terminal value because of
Discuss
Answer & Solution
Answer: Option D
Solution:
The velocity of falling rain drops attains a terminal value because of viscous force exerted by air.
80
Which one is the unit of surface tension of a liquid
Discuss
Answer & Solution
Answer: Option B
Solution:
The unit of surface tension of a liquid is Electron volt /cm2.