Question
91
General Science
Which of the following conditions is most essential for the rusting of iron to occur?
(A)
Presence of only oxygen
(B)
Presence of only carbon dioxide
(C)
Presence of both oxygen and water (or moisture)
(D)
Presence of sunlight
Correct Answer:
Presence of both oxygen and water (or moisture)
Explanation:
Both oxygen and water or moisture are necessary for iron to rust. During this process, iron is oxidized to form hydrated iron(III) oxide, commonly known as rust.
Both oxygen and water or moisture are necessary for iron to rust. During this process, iron is oxidized to form hydrated iron(III) oxide, commonly known as rust.
Question
92
Physics
Why does a drinking straw work to draw a soft drink up into your mouth?
(A)
The straw creates a vacuum that pulls the liquid up
(B)
Atmospheric pressure pushes the liquid up into the region of lower pressure created in the straw when you suck
(C)
The liquid is naturally attracted to the plastic of the straw
(D)
Gravity pulls the liquid upward
Correct Answer:
Atmospheric pressure pushes the liquid up into the region of lower pressure created in the straw when you suck
Explanation:
When we suck through a straw, the pressure inside the straw decreases. Atmospheric pressure acting on the surface of the drink is then greater and pushes the liquid upward through the straw.
When we suck through a straw, the pressure inside the straw decreases. Atmospheric pressure acting on the surface of the drink is then greater and pushes the liquid upward through the straw.
Question
93
Chemistry
A farmer finds that the soil in his field is highly acidic, which is affecting the growth of his crops. Which of the following substances should he add to the soil to neutralize the acidity and improve crop yield?
(A)
Vinegar (acetic acid)
(B)
Lemon juice (citric acid)
(C)
Slaked lime (calcium hydroxide)
(D)
Common salt (sodium chloride)
Correct Answer:
Slaked lime (calcium hydroxide)
Explanation:
Alkaline substances are used to neutralize acidic soil. Slaked lime, or calcium hydroxide, is a base that helps reduce excess acidity in the soil.
Alkaline substances are used to neutralize acidic soil. Slaked lime, or calcium hydroxide, is a base that helps reduce excess acidity in the soil.
Question
94
Biology
Which of the following helps a camel survive for long periods without water in the desert?
(A)
It stores water in its hump
(B)
It sweats a lot to keep its body cool
(C)
It produces very concentrated urine and dry dung
(D)
It drinks water only once in a year
Correct Answer:
It produces very concentrated urine and dry dung
Explanation:
A camel produces highly concentrated urine and dry dung to minimize water loss. Its hump does not store water; it stores fat, which can provide energy when food is scarce.
A camel produces highly concentrated urine and dry dung to minimize water loss. Its hump does not store water; it stores fat, which can provide energy when food is scarce.
Question
95
Physics
If the angle of incidence of a light ray striking a plane mirror is 40 degrees, what will be the angle between the incident ray and the reflected ray?
(A)
40 degrees
(B)
50 degrees
(C)
80 degrees
(D)
100 degrees
Correct Answer:
80 degrees
Explanation:
According to the law of reflection, the angle of incidence is equal to the angle of reflection. Therefore, the angle of reflection is 40 degrees. The angle between the incident and reflected rays is the sum of the two angles: 40 + 40 = 80 degrees.
According to the law of reflection, the angle of incidence is equal to the angle of reflection. Therefore, the angle of reflection is 40 degrees. The angle between the incident and reflected rays is the sum of the two angles: 40 + 40 = 80 degrees.
Question
96
Biology
Which of the following characteristics in humans is an example of an acquired trait, and therefore cannot be passed on to the next generation?
(A)
Eye color (blue, brown, black)
(B)
Blood group (A, B, AB, O)
(C)
The ability to speak a particular language, such as French or Hindi
(D)
The shape of the earlobe (attached or free)
Correct Answer:
The ability to speak a particular language, such as French or Hindi
Explanation:
The ability to speak a particular language is developed through learning and environmental influence. It is an acquired trait and is generally not inherited genetically by the next generation.
The ability to speak a particular language is developed through learning and environmental influence. It is an acquired trait and is generally not inherited genetically by the next generation.
Question
97
Agriculture
Which of the following methods of irrigation is most water-efficient and is widely promoted in water-scarce regions to minimize water wastage?
(A)
Sprinkler system
(B)
Drip irrigation
(C)
Canal irrigation
(D)
Flood irrigation
Correct Answer:
Drip irrigation
Explanation:
In drip irrigation, water is delivered drop by drop directly near the roots of plants through pipes and emitters. This minimizes water loss due to evaporation and runoff, making it a highly water-efficient irrigation method.
In drip irrigation, water is delivered drop by drop directly near the roots of plants through pipes and emitters. This minimizes water loss due to evaporation and runoff, making it a highly water-efficient irrigation method.
Question
98
Chemistry
You add sugar to a glass of water and stir continuously. After some time, no more sugar dissolves, and the undissolved sugar settles at the bottom. What is this solution called?
(A)
Unsaturated solution
(B)
Saturated solution
(C)
Supersaturated solution
(D)
Dilute solution
Correct Answer:
Saturated solution
Explanation:
When the maximum amount of sugar has dissolved in water at a given temperature and additional sugar remains undissolved and settles at the bottom, the solution is called a saturated solution.
When the maximum amount of sugar has dissolved in water at a given temperature and additional sugar remains undissolved and settles at the bottom, the solution is called a saturated solution.
Question
99
Physics
Why are electric wires used in household wiring made of copper or aluminium, while the heating element in an electric iron is made of nichrome?
(A)
Copper is cheaper than nichrome
(B)
Copper has very low resistance, so it does not waste electricity as heat, while nichrome has high resistance to produce heat
(C)
Copper is stronger than nichrome
(D)
Nichrome is a better conductor than copper
Correct Answer:
Copper has very low resistance, so it does not waste electricity as heat, while nichrome has high resistance to produce heat
Explanation:
Copper and aluminium are good electrical conductors and have low resistance, so unnecessary loss of electrical energy as heat is minimized in household wiring. In contrast, nichrome has high resistance, so it produces more heat when electric current passes through it and is therefore suitable for heating elements.
Copper and aluminium are good electrical conductors and have low resistance, so unnecessary loss of electrical energy as heat is minimized in household wiring. In contrast, nichrome has high resistance, so it produces more heat when electric current passes through it and is therefore suitable for heating elements.
Question
100
Physics
Which of the following units is used to measure the intensity or loudness of sound?
(A)
Hertz
(B)
Meter per second
(C)
Decibel
(D)
Watt
Correct Answer:
Decibel
Explanation:
The loudness or sound level is measured in decibels (dB). Hertz is the unit of frequency, while metre per second is a unit of speed.
The loudness or sound level is measured in decibels (dB). Hertz is the unit of frequency, while metre per second is a unit of speed.
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