Exams > NCERT > Science Technology
SCIENCE BASIC QUESTIONS MCQs
Total Questions : 10
Answer: Option A. -> Adenosine Triphosphate (ATP)
:
A
Explanation:
Adenosine triphosphate (ATP) is an organic compound that provides energy to drive many processes in living cells. Found in all forms of life, ATP is sometimes referred to as the intracellular energy transfer 'molecular unit of currency.' It transforms either to adenosine diphosphate (ADP) or to adenosine monophosphate (AMP), when ingested in metabolic processes. Many mechanisms replace ATP, so that every day the human body recycles its own equal body weight in ATP. It is also a precursor to DNA and RNA, and is used as a coenzyme.
:
A
Explanation:
Adenosine triphosphate (ATP) is an organic compound that provides energy to drive many processes in living cells. Found in all forms of life, ATP is sometimes referred to as the intracellular energy transfer 'molecular unit of currency.' It transforms either to adenosine diphosphate (ADP) or to adenosine monophosphate (AMP), when ingested in metabolic processes. Many mechanisms replace ATP, so that every day the human body recycles its own equal body weight in ATP. It is also a precursor to DNA and RNA, and is used as a coenzyme.
Question 2. Q. Consider the following statements with reference to Isotopes:
Which of the above given statements is/are incorrect?
- Isotopes are atoms having the same mass number but different atomic number.
- Isotopes of cobalt is used in treatment of cancer
- The physical properties of Isotopes are similar but their chemical properties are different.
Which of the above given statements is/are incorrect?
Answer: Option D. -> 1 and 3 only
:
D
Explanation:
Statement 1 is incorrect: Isotopes are those elements having the same atomic number and different mass number. In isotopes the atoms have different numbers of neutrons but the number of protons remains the same.
Statement 2 is correct: Some Isotopes have special properties which makes them useful:
Statement 3 is incorrect: Each isotope of an element is a pure substance, the chemical properties of Isotopes are similar but their physical properties are different. Isobar is that element which differs in the chemical property but has the same physical property.
:
D
Explanation:
Statement 1 is incorrect: Isotopes are those elements having the same atomic number and different mass number. In isotopes the atoms have different numbers of neutrons but the number of protons remains the same.
Statement 2 is correct: Some Isotopes have special properties which makes them useful:
- An isotope of Uranium is used in Nuclear reactors as fuel
- An isotope of Cobalt is used in the treatment of cancer
- An isotope of Iodine is used in treatment of Goitre
Statement 3 is incorrect: Each isotope of an element is a pure substance, the chemical properties of Isotopes are similar but their physical properties are different. Isobar is that element which differs in the chemical property but has the same physical property.
Answer: Option D. -> Bakelite
:
D
Explanation:
Bakelite and Melamine are examples of thermosetting plastics. They are a type of plastic which when moulded once cannot be softened by heating unlike a thermoplastic.
Note: A thermoplastic, or thermosoftening plastic, is a plastic polymer material that becomes pliable or moldable at a certain elevated temperature and solidifies upon cooling. Polyethylene, polypropylene, polyvinyl chloride (pvc), acrylic, nylon and Teflon are examples of thermoplastics.
:
D
Explanation:
Bakelite and Melamine are examples of thermosetting plastics. They are a type of plastic which when moulded once cannot be softened by heating unlike a thermoplastic.
Note: A thermoplastic, or thermosoftening plastic, is a plastic polymer material that becomes pliable or moldable at a certain elevated temperature and solidifies upon cooling. Polyethylene, polypropylene, polyvinyl chloride (pvc), acrylic, nylon and Teflon are examples of thermoplastics.
Question 4. Q. With reference to physical and chemical change consider the following statements:
Which of the above given statements is/are correct?
- In physical change the molecules are rearranged and do not affect the internal structure of a substance.
- Physical change involves high energy absorption, while chemical change results in little energy absorption.
- Melting of ice and evaporation are examples of physical change.
Which of the above given statements is/are correct?
Answer: Option B. -> 1 and 3 only
:
B
Explanation:
Statement 1 is correct: A substance is said to undergo a physical change if only the physical properties such as the substance's form, size, colour, state or appearance change. It remains unchanged as to its chemical composition. Some of the characteristics of a physical change are:
Statement 2 is incorrect: Physical change involves very little or no energy is released. When the chemical properties of a substance alter, a substance is said to undergo a chemical change. As a consequence, at the molecular level, atomic bonds are either formed or breached. Some of the characteristics of a chemical change are:
Statement 3 is correct: Some of the examples of a physical change are freezing and boiling of water, melting of ice, condensation, magnetizing a compass needle, vaporization, dissolving sugar in water, etc.
:
B
Explanation:
Statement 1 is correct: A substance is said to undergo a physical change if only the physical properties such as the substance's form, size, colour, state or appearance change. It remains unchanged as to its chemical composition. Some of the characteristics of a physical change are:
- Temporary in nature.
- Does not affect the internal structure of a substance, only the molecules are rearranged.
- Very little or no energy is released
- No new substance is formed.
- Most of the physical changes are reversible. We can obtain the substance back even after the change.
Statement 2 is incorrect: Physical change involves very little or no energy is released. When the chemical properties of a substance alter, a substance is said to undergo a chemical change. As a consequence, at the molecular level, atomic bonds are either formed or breached. Some of the characteristics of a chemical change are:
- Permanent in nature.
- Since the original composition of the substance changes, one or more new substances are formed.
- Forms of energy, such as heat, light or electricity, may be emitted or absorbed.
- A chemical change is generally irreversible. At least, it cannot be reversed by simple physical means.
Statement 3 is correct: Some of the examples of a physical change are freezing and boiling of water, melting of ice, condensation, magnetizing a compass needle, vaporization, dissolving sugar in water, etc.
Answer: Option C. -> Hydrochloric acid and Nitric acid
:
C
Explanation:
Aqua regia ("regal water" or "Royal water ") is a mixture of nitric acid and hydrochloric acid, optimally in a molar ratio of 1:3. Aqua regia is a fuming liquid of yellow-orange (sometimes red), so called by alchemists because it can dissolve the noble metals, gold and platinum, but not all metals. Aqua Regia is called "Magic Water" or "King's Water," since they can remove gold and platinum from the magic metal.
:
C
Explanation:
Aqua regia ("regal water" or "Royal water ") is a mixture of nitric acid and hydrochloric acid, optimally in a molar ratio of 1:3. Aqua regia is a fuming liquid of yellow-orange (sometimes red), so called by alchemists because it can dissolve the noble metals, gold and platinum, but not all metals. Aqua Regia is called "Magic Water" or "King's Water," since they can remove gold and platinum from the magic metal.
Answer: Option B. -> 1, 2 and 3 only
:
B
Explanation:
Vestigial organs are the organs which have no apparent function and are considered the residual parts of the ancestors of the past. Such a structure may develop as a result of gene mutation that causes protein changes. These mutated proteins are causing vestigial structures to form.
Option 1, 2 and 3 are correct: Following are a few examples of vestigial organs:
Sinuses
Human cheekbones have maxillary sinuses in their hold. The face is made of air pockets, called sinuses. A thin layer of mucosa lines them out. It has no significant use but can lead to sinusitis from infection.
Appendix
It is one of the most widely known. Closed at one end, this finger-like tube emerges from the vermiform process. In prime ancestors, it is assumed that the appendix has brought about cellulose digestion.
Tonsils
The tonsils remain within the human body as vestigial organs. They act as the first line of protection and defend the body from harmful microorganisms which are inhaled or ingested to the body.
Statement 4 and 5 are incorrect: Inner Ear and Hypodermis are not vestigial organs.
:
B
Explanation:
Vestigial organs are the organs which have no apparent function and are considered the residual parts of the ancestors of the past. Such a structure may develop as a result of gene mutation that causes protein changes. These mutated proteins are causing vestigial structures to form.
Option 1, 2 and 3 are correct: Following are a few examples of vestigial organs:
Sinuses
Human cheekbones have maxillary sinuses in their hold. The face is made of air pockets, called sinuses. A thin layer of mucosa lines them out. It has no significant use but can lead to sinusitis from infection.
Appendix
It is one of the most widely known. Closed at one end, this finger-like tube emerges from the vermiform process. In prime ancestors, it is assumed that the appendix has brought about cellulose digestion.
Tonsils
The tonsils remain within the human body as vestigial organs. They act as the first line of protection and defend the body from harmful microorganisms which are inhaled or ingested to the body.
Statement 4 and 5 are incorrect: Inner Ear and Hypodermis are not vestigial organs.
Question 7. Q. Consider the following statements with reference to sound:
Which of the above given statements is correct?
- Sonic boom is caused by an object travelling at supersonic speed.
- Unlike light, sound does not reflect from a harder flat surface called specular reflection.
- Principle of reverberation of sound is used in the stethoscope to hear a patient's heartbeat.
Which of the above given statements is correct?
Answer: Option D. -> 1 and 3 only
:
D
Explanation:
Statement 1 is correct: When an object travels at a speed greater than the speed of sound in air, it is said to be travelling with a supersonic speed. Enormous energy is produced when an object travels at a supersonic speed. This energy is propagated as a sharp and loud sound, called a sonic boom.
Statement 2 is incorrect: When the sound wave is reflected by a surface then the incident wave, reflected wave and the normal at the point of incidence all lie in the same plane. Similar to reflection of light from a mirror, sound also reflects from a harder flat surface. This is called specular reflection. Both light and sound reflects from a harder flat surface.
Statement 3 is correct: Reverberation is the phenomenon of persistence of sound (though the source has stopped producing sound) as a result of multiple reflections from a closed surface. Stethoscope which is used to hear the sounds of internal organs of a patient works on the principle of reverberation.
:
D
Explanation:
Statement 1 is correct: When an object travels at a speed greater than the speed of sound in air, it is said to be travelling with a supersonic speed. Enormous energy is produced when an object travels at a supersonic speed. This energy is propagated as a sharp and loud sound, called a sonic boom.
Statement 2 is incorrect: When the sound wave is reflected by a surface then the incident wave, reflected wave and the normal at the point of incidence all lie in the same plane. Similar to reflection of light from a mirror, sound also reflects from a harder flat surface. This is called specular reflection. Both light and sound reflects from a harder flat surface.
Statement 3 is correct: Reverberation is the phenomenon of persistence of sound (though the source has stopped producing sound) as a result of multiple reflections from a closed surface. Stethoscope which is used to hear the sounds of internal organs of a patient works on the principle of reverberation.
Answer: Option B. -> An instrument used to measure distance travelled by moving vehicle
:
B
Explanation:
Option (a) is incorrect: Pitometer logs (also known as pit logs) are devices used to measure a ship's speed relative to the water.
Option (b) is correct: An odometer or odograph is an instrument used for measuring the distance traveled by a vehicle, such as a bicycle or car. The device may be electronic, mechanical, or a combination of the two (electromechanical).
Option (c) is incorrect: An opisometer, also called a curvimeter, meilograph, or map measurer, is an instrument for measuring the lengths of arbitrary curved lines.
Option (d) is incorrect: Sonar is a device for finding objects underwater using sound waves. Sonars transmit ultrasonic waves into the water below and receive the returning echoes from the seabed.
:
B
Explanation:
Option (a) is incorrect: Pitometer logs (also known as pit logs) are devices used to measure a ship's speed relative to the water.
Option (b) is correct: An odometer or odograph is an instrument used for measuring the distance traveled by a vehicle, such as a bicycle or car. The device may be electronic, mechanical, or a combination of the two (electromechanical).
Option (c) is incorrect: An opisometer, also called a curvimeter, meilograph, or map measurer, is an instrument for measuring the lengths of arbitrary curved lines.
Option (d) is incorrect: Sonar is a device for finding objects underwater using sound waves. Sonars transmit ultrasonic waves into the water below and receive the returning echoes from the seabed.
Answer: Option C. -> 1 and 2 only
:
C
Explanation:
If atmospheric pollutants such as nitrogen oxides and sulphur react with rainwater and come down with the rain, it results in Acid Rain. The causes of acid rain are particles of sulfur and nitrogen that are mixed with the wet components of rain.
Statement 1 is correct: The basic constituents of acid rain that make it acidic are: Nitrogen dioxide, carbon dioxide, sulphur dioxide and carbonic acid.
Statement 2 is correct: The oxides of nitrogen and sulphur, when released as pollutants in the atmosphere, dissolve in rain drops to form carbonic acid, Nitric acid and sulphuric acid.
Statement 3 is incorrect: Nitrous oxide is a neutral oxide of Nitrogen. Neutral oxides are those oxides which show neither basic or acidic properties when they react with water. It is emitted during agricultural activities, combustion of fossil fuels and solid waste. Carbon monoxide (CO) which is only slightly soluble in water is also a neutral oxide.
:
C
Explanation:
If atmospheric pollutants such as nitrogen oxides and sulphur react with rainwater and come down with the rain, it results in Acid Rain. The causes of acid rain are particles of sulfur and nitrogen that are mixed with the wet components of rain.
Statement 1 is correct: The basic constituents of acid rain that make it acidic are: Nitrogen dioxide, carbon dioxide, sulphur dioxide and carbonic acid.
Statement 2 is correct: The oxides of nitrogen and sulphur, when released as pollutants in the atmosphere, dissolve in rain drops to form carbonic acid, Nitric acid and sulphuric acid.
Statement 3 is incorrect: Nitrous oxide is a neutral oxide of Nitrogen. Neutral oxides are those oxides which show neither basic or acidic properties when they react with water. It is emitted during agricultural activities, combustion of fossil fuels and solid waste. Carbon monoxide (CO) which is only slightly soluble in water is also a neutral oxide.
Question 10. Q. Consider the following statements, with reference to Algae:
Which of the above given statements is correct?
- Algae generally thrive in nutrients rich water.
- Algae can be used to produce Bioplastics.
- Proteins are found in microalgae.
- Algae are found in all environments except snowy regions.
Which of the above given statements is correct?
Answer: Option D. -> 1, 2 and 3 only
:
D
Explanation:
Alga is a term that describes a large and incredibly diverse group of eukaryotic, photosynthetic life forms. It can be unicellular or multicellular.
Statement 1 is correct: Algae flourish in nutrient-rich waters such as urban wastewater (sewage), animal waste and some industrial effluents, while at the same time purifying such waste and creating a biomass suitable for biofuels.
Statement 2 is correct: Algae produce a variety of base materials that can be used for bioplastics production. Most important are carbohydrates and hydrocarbons
Statement 3 is correct: Microalgae contain similar raw materials as traditional crops: high-quality oils, proteins, pigments as well as hydrocarbons and sugars.
Statement 4 is incorrect: Algae can survive in snowy regions too. They live in ocean to pond environments. It is commonly green, but can be found in a number of colours. In addition to chlorophyll, for example, algae living in snow produce carotenoid pigments, thus giving the surrounding snow a distinctive red colour.
:
D
Explanation:
Alga is a term that describes a large and incredibly diverse group of eukaryotic, photosynthetic life forms. It can be unicellular or multicellular.
Statement 1 is correct: Algae flourish in nutrient-rich waters such as urban wastewater (sewage), animal waste and some industrial effluents, while at the same time purifying such waste and creating a biomass suitable for biofuels.
Statement 2 is correct: Algae produce a variety of base materials that can be used for bioplastics production. Most important are carbohydrates and hydrocarbons
Statement 3 is correct: Microalgae contain similar raw materials as traditional crops: high-quality oils, proteins, pigments as well as hydrocarbons and sugars.
Statement 4 is incorrect: Algae can survive in snowy regions too. They live in ocean to pond environments. It is commonly green, but can be found in a number of colours. In addition to chlorophyll, for example, algae living in snow produce carotenoid pigments, thus giving the surrounding snow a distinctive red colour.
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