Daily Updates Mock Test 111
MOCK TEST 111
SYLLABUS : GENERAL SCIENCE
TIME : 20 MINUTES FULL MARKS : 50*5 = 250
আজকের মোক টেস্ট নেওয়া হবে 9.00 PM ( 01/04/2019 ) থেকে , এই মোক টেস্ট দেওয়া যাবে কাল ( 02/04/2019 ) সকাল 11 টা পর্যন্ত
EACH QUESTION CARRIES 5 MARKS , -VE MARKING = - 1 / WRONG ANSWER
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Questions and Answers
- 1.
Genus of goat is
- A.
Ovis
- B.
Copra
- C.
Bos
- D.
Bubalus
Correct Answer
B. Copra -
- 2.
‘Splenic fever’ is another name for
- A.
FMD
- B.
Anthrax
- C.
Cow pox
- D.
Mastitis
Correct Answer
B. AnthraxExplanation
Anthrax is commonly referred to as "splenic fever." It is a serious infectious disease caused by the bacterium Bacillus anthracis. Anthrax affects both animals and humans and can be transmitted through contact with infected animals or their products. The name "splenic fever" is derived from the fact that the disease often leads to enlargement and hemorrhage of the spleen.Rate this question:
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- 3.
‘Pashmina wool’ is obtained from
- A.
Yak
- B.
Cattle
- C.
Sheep
- D.
Goat
Correct Answer
D. GoatExplanation
Pashmina wool is obtained from goats. Pashmina is a type of fine cashmere wool that comes from the undercoat of certain breeds of goats, particularly the Changthangi goat found in the Himalayan region. These goats have a thick and soft undercoat that keeps them warm in the harsh mountain climate. The wool is collected by combing or shearing the goats, and then it is spun and woven into luxurious and warm fabrics. Pashmina wool is highly prized for its softness, warmth, and durability, making it a popular choice for high-quality shawls, scarves, and other luxury garments.Rate this question:
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- 4.
Rickets is due to deficiency of
- A.
Vitamin C
- B.
Vitamin D
- C.
Vitamin A
- D.
Vitamin B12
Correct Answer
B. Vitamin DExplanation
Rickets is a condition that is caused by a deficiency of vitamin D. Vitamin D plays a crucial role in the absorption of calcium and phosphorus, which are essential for the development and maintenance of strong and healthy bones. When there is a lack of vitamin D, the body is unable to properly absorb these minerals, leading to soft and weak bones. This can result in symptoms such as bone pain, skeletal deformities, and an increased risk of fractures. Therefore, the correct answer is vitamin D.Rate this question:
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- 5.
Ranikhet is a ___________ disease
- A.
Viral
- B.
Mematode
- C.
Bacterial
- D.
Fungal
Correct Answer
A. ViralExplanation
Ranikhet is a viral disease because it is caused by a virus. Viruses are microscopic infectious agents that can only replicate inside the cells of a living organism. They can cause a wide range of diseases in humans, animals, and plants. In the case of Ranikhet, it is a viral disease that primarily affects poultry, causing respiratory and nervous system symptoms.Rate this question:
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- 6.
The main thinking part of the brain is
- A.
midbrain
- B.
Hypothalamus
- C.
Forebrain
- D.
hindbrain
Correct Answer
C. ForebrainExplanation
The forebrain is the correct answer because it is responsible for the higher cognitive functions such as thinking, reasoning, and problem-solving. It is the largest part of the brain and includes the cerebral cortex, which plays a crucial role in processing sensory information and controlling voluntary movements. The forebrain also houses important structures like the thalamus and hypothalamus, which are involved in regulating emotions, sleep, and hormone production. Overall, the forebrain is essential for complex cognitive processes and plays a major role in our thinking abilities.Rate this question:
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- 7.
Which one among the following hormones stimulates the plant cells to grow in a manner such that the plant appears to be bent towards light?
- A.
Cytokinin
- B.
Auxin
- C.
Gibberellin
- D.
Abscisic acid
Correct Answer
B. AuxinExplanation
Auxin is the correct answer because it is a hormone that stimulates plant cell elongation and growth. When light is unevenly distributed, auxin accumulates on the shaded side of the plant, causing cells to elongate more on that side. This results in the plant bending towards the light source.Rate this question:
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- 8.
The sex of a newborn baby is determined by the chromosome inherited from
- A.
The mother
- B.
the father
- C.
Mother’s mother
- D.
father’s father
Correct Answer
B. the fatherExplanation
The sex of a newborn baby is determined by the chromosome inherited from the father. This is because the father can contribute either an X or a Y chromosome during fertilization, while the mother always contributes an X chromosome. If the baby receives an X chromosome from the father, it will be female (XX), and if it receives a Y chromosome, it will be male (XY). Therefore, the father's chromosome is the determining factor in the baby's sex.Rate this question:
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- 9.
Average life span of human R.B.C is
- A.
80 days
- B.
90 days
- C.
120 days
- D.
None of these
Correct Answer
C. 120 daysExplanation
The average life span of a human red blood cell (R.B.C) is 120 days. Red blood cells are responsible for carrying oxygen to various parts of the body. They have a limited life span due to the wear and tear they experience while performing their function. After about 120 days, old and damaged red blood cells are removed from circulation and replaced by new ones produced in the bone marrow. Therefore, the correct answer is 120 days.Rate this question:
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- 10.
Which of the following disease is caused by bacteria ?
- A.
Athlete’s foot
- B.
Tuberculosis
- C.
Ringworm
- D.
Thrush
Correct Answer
B. TuberculosisExplanation
Tuberculosis is caused by bacteria called Mycobacterium tuberculosis. It primarily affects the lungs but can also affect other parts of the body. The bacteria spread through the air when an infected person coughs or sneezes. It is a contagious disease and can be transmitted from person to person. Symptoms of tuberculosis include coughing, chest pain, fatigue, weight loss, and night sweats. Treatment usually involves a combination of antibiotics taken for several months to effectively kill the bacteria.Rate this question:
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- 11.
Death by diarrhoea in children is caused mainly by
- A.
Bacteria
- B.
Protozoa
- C.
Amoeba
- D.
Fungus
Correct Answer
A. BacteriaExplanation
Death by diarrhoea in children is mainly caused by bacteria. Bacterial infections such as Escherichia coli, Salmonella, and Shigella are common causes of diarrhoea in children, particularly in developing countries with poor sanitation and hygiene practices. These bacteria can contaminate food and water sources, leading to severe gastrointestinal symptoms and dehydration. Prompt treatment with antibiotics and rehydration therapy is crucial to prevent complications and reduce mortality rates associated with bacterial diarrhoea in children. Protozoa, amoeba, and fungus can also cause diarrhoea, but they are less common causes compared to bacteria.Rate this question:
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- 12.
Diseases of which of the following pairs are caused by virus?
- A.
Malaria and Polio
- B.
Polio and Bird Flu
- C.
Polio and Tuberculosis
- D.
Tuberculosis and Influenza
Correct Answer
B. Polio and Bird FluExplanation
Polio and Bird Flu are caused by viruses. Polio is caused by the poliovirus, which primarily affects the nervous system and can lead to paralysis. Bird Flu, also known as avian influenza, is caused by various strains of the influenza A virus that primarily infect birds but can also infect humans. Both diseases are viral in nature and are caused by specific viruses.Rate this question:
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- 13.
The liver disease Hepatitis-B is caused by
- A.
Virus
- B.
Protozoa
- C.
Bacterium
- D.
Platyhelminth
Correct Answer
A. VirusExplanation
Hepatitis-B is a liver disease caused by a virus.Rate this question:
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- 14.
The radio isotope used to control blood cancer(leukaemia) is
- A.
Iodine-131
- B.
Sodium-24
- C.
Phosphorus-32
- D.
Cobalt-60
Correct Answer
D. Cobalt-60Explanation
Cobalt-60 is the correct answer because it is commonly used in radiation therapy to treat blood cancer, specifically leukemia. It emits high-energy gamma rays that can target and destroy cancer cells. Cobalt-60 is preferred for its ability to penetrate deep into tissues, making it effective in treating cancers that have spread or are located in hard-to-reach areas. Its use in cancer treatment has been well-established and proven effective over the years.Rate this question:
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- 15.
pH of human blood is
- A.
7.4
- B.
6.2
- C.
9.0
- D.
7.5 – 8.0
Correct Answer
A. 7.4Explanation
The pH of human blood is 7.4. pH is a measure of the acidity or alkalinity of a solution, with 7 being neutral. The pH of blood is tightly regulated to maintain homeostasis and ensure proper functioning of the body. A pH of 7.4 is slightly alkaline, which is necessary for optimal enzyme activity and oxygen transport. Deviations from this pH can have detrimental effects on various physiological processes.Rate this question:
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- 16.
The normal temperature of human body on the Kelvin scale is
- A.
280K
- B.
290K
- C.
300K
- D.
310K
Correct Answer
D. 310KExplanation
The normal temperature of the human body is 310K on the Kelvin scale. The Kelvin scale is an absolute temperature scale where 0K represents absolute zero, the point at which all molecular motion ceases. The normal body temperature is around 37 degrees Celsius or 98.6 degrees Fahrenheit, which is equivalent to 310K on the Kelvin scale.Rate this question:
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- 17.
The only snake that builds a nest is
- A.
Chain viper
- B.
King cobra
- C.
Krait
- D.
Saw-scaled viper
Correct Answer
B. King cobraExplanation
The correct answer is King cobra because it is the only snake among the options listed that builds a nest. King cobras are known for constructing large, elaborate nests made of leaves, twigs, and other materials. These nests serve as a safe place for the female king cobra to lay her eggs and provide protection for the developing offspring. Unlike other snakes that may lay their eggs in hidden locations or simply leave them in a suitable environment, the king cobra actively constructs a nest, making it unique in this behavior.Rate this question:
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- 18.
Which of the following harmones contains Iodine ?
- A.
Thyroxine
- B.
Testosterone
- C.
Insulin
- D.
Adrenaline
Correct Answer
A. ThyroxineExplanation
Thyroxine is the correct answer because it is a hormone produced by the thyroid gland that contains iodine. Iodine is an essential component of thyroxine and is necessary for the synthesis of this hormone. Thyroxine plays a crucial role in regulating metabolism, growth, and development in the body. Testosterone, insulin, and adrenaline do not contain iodine and have different functions in the body.Rate this question:
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- 19.
Arteries supplying blood to the heart are called
- A.
Carotid arteries
- B.
Hepatic arteries
- C.
Coronary arteries
- D.
Pulmonary arteries
Correct Answer
C. Coronary arteriesExplanation
The arteries that supply blood to the heart are called coronary arteries. These arteries are responsible for delivering oxygen-rich blood to the heart muscle itself, ensuring that it can function properly. The carotid arteries supply blood to the brain, the hepatic arteries supply blood to the liver, and the pulmonary arteries supply blood to the lungs. However, none of these arteries specifically supply blood to the heart. Therefore, the correct answer is coronary arteries.Rate this question:
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- 20.
Antigen is a substance which
- A.
Lowers body temperature
- B.
Destroys WBC
- C.
Triggers the immune system
- D.
is used as an antidote to poison
Correct Answer
C. Triggers the immune systemExplanation
An antigen is a substance that triggers the immune system. When the immune system detects an antigen, it initiates an immune response to eliminate the foreign substance from the body. This response includes the production of antibodies that specifically target and neutralize the antigen, as well as the activation of immune cells to destroy any cells infected or affected by the antigen. Therefore, the correct answer is "triggers the immune system".Rate this question:
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- 21.
Which of the following has the largest number of chromosomes ?
- A.
Human beings
- B.
Pteridophytes
- C.
Elephants
- D.
Bryophytes
Correct Answer
B. PteridophytesExplanation
Pteridophytes have the largest number of chromosomes among the given options. Pteridophytes are a group of plants that include ferns and horsetails. These plants have a complex life cycle and reproduce through spores. They typically have a higher number of chromosomes compared to other organisms. Human beings have 46 chromosomes, elephants have 56 chromosomes, and bryophytes (which include mosses and liverworts) have a relatively lower number of chromosomes. Therefore, pteridophytes have the largest number of chromosomes among the given options.Rate this question:
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- 22.
The pollination by snail is called
- A.
Zoophily
- B.
Entomophily
- C.
Chiropteriphily
- D.
Malacophily
Correct Answer
D. MalacophilyExplanation
Malacophily refers to the pollination of plants by snails. This is a type of pollination where snails play a role in transferring pollen from the male reproductive organs of a flower to the female reproductive organs of another flower. Unlike other forms of pollination, such as zoophily (pollination by animals) or entomophily (pollination by insects), malacophily specifically involves snails as the pollinators.Rate this question:
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- 23.
Which of the following vitamins acts like hormone ?
- A.
Vitamin A
- B.
Vitamin B
- C.
Vitamin C
- D.
Vitamin D
Correct Answer
D. Vitamin DExplanation
Vitamin D acts like a hormone in the body. It is synthesized in the skin when exposed to sunlight and plays a crucial role in calcium absorption and bone health. It acts as a hormone by regulating the expression of genes involved in various bodily functions, including immune system regulation, cell growth, and inflammation. Unlike other vitamins, vitamin D can be synthesized by the body and also obtained through certain foods and supplements.Rate this question:
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- 24.
The theory of mutation was propounded by
- A.
De-vries
- B.
Malpighi
- C.
Robert Hooke
- D.
Pasteur
Correct Answer
A. De-vriesExplanation
De Vries is credited with formulating the theory of mutation, also known as the mutation theory of evolution. He proposed that new species arise through sudden and abrupt changes in hereditary traits, which he called mutations. This theory challenged the prevailing belief of gradual evolution through natural selection proposed by Charles Darwin. De Vries's work on mutations and his theory had a significant impact on the field of genetics and contributed to our understanding of how new species can arise.Rate this question:
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- 25.
The word gene was firstly used by
- A.
Waldare
- B.
Watson
- C.
Crick
- D.
Johannsen
Correct Answer
D. JohannsenExplanation
The correct answer is Johannsen because he was the first to use the term "gene" in his work on heredity and genetics in the early 20th century. Johannsen coined the term to describe the fundamental unit of heredity, which he believed to be responsible for transmitting traits from parents to offspring. His usage of the word gene became widely accepted and is still used in modern genetics.Rate this question:
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- 26.
Who was the discoverer of human blood groups?
- A.
Landsteiner
- B.
Livine
- C.
Vinear
- D.
Leeuwenhoek
Correct Answer
A. LandsteinerExplanation
The correct answer is Landsteiner. Landsteiner, an Austrian immunologist and pathologist, is credited with the discovery of human blood groups. In 1901, he identified the ABO blood group system, which classified blood into different types based on the presence or absence of certain antigens on red blood cells. This discovery was a significant breakthrough in the field of transfusion medicine and paved the way for safe blood transfusions.Rate this question:
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- 27.
Which of the following blood group is called universal donor ?
- A.
A+
- B.
B+
- C.
O+
- D.
AB+
Correct Answer
C. O+Explanation
O+ is considered the universal donor blood group because it lacks both A and B antigens on its red blood cells. This means that O+ blood can be safely transfused to individuals with any blood type, as it is less likely to cause an immune response. However, it is important to note that O+ blood should only be given to individuals with Rh positive blood types to avoid complications.Rate this question:
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- 28.
Which part of the human brain regulates sleep ?
- A.
Medulla oblongata
- B.
Cerebellum
- C.
Pineal gland
- D.
Pituitary gland
Correct Answer
C. Pineal glandExplanation
The pineal gland is a small endocrine gland located in the brain that produces the hormone melatonin. Melatonin is involved in the regulation of the sleep-wake cycle and helps to control the timing and duration of sleep. It is released in response to darkness and helps to promote sleep. Therefore, the pineal gland plays a crucial role in regulating sleep in the human brain.Rate this question:
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- 29.
The leading probiotic drink yakult contains which of the following bacterium ?
- A.
Escherichia coli
- B.
Lactobacillus casei
- C.
Saccharomyces cerevisiae
- D.
Lactobacillus plantarum
Correct Answer
B. Lactobacillus caseiExplanation
Yakult is a leading probiotic drink that contains Lactobacillus casei. Lactobacillus casei is a type of beneficial bacteria that is commonly found in the human digestive system. It is known for its ability to promote digestive health by helping to maintain a healthy balance of bacteria in the gut. Consuming Yakult, which contains Lactobacillus casei, can help support a healthy digestive system and improve overall gut health.Rate this question:
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- 30.
The organ of the human body which stores the carbohydrates in the form of glycogen is
- A.
intestine
- B.
Stomach
- C.
Pancreas
- D.
liver
Correct Answer
D. liverExplanation
The liver is the correct answer because it plays a crucial role in carbohydrate metabolism. It stores excess glucose in the form of glycogen and releases it when the body needs energy. The liver acts as a storage organ for carbohydrates, ensuring a steady supply of glucose to the body when required.Rate this question:
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- 31.
Which of the following is the example of ideal black body
- A.
Kajal
- B.
Black board
- C.
A pin hole box
- D.
None of these
Correct Answer
C. A pin hole boxExplanation
A pin hole box can be considered an example of an ideal black body because it absorbs all incoming radiation and emits radiation uniformly in all directions. The small pin hole allows only a minimal amount of light to enter, ensuring that the majority of the radiation is absorbed by the interior walls of the box. This absorption and emission behavior is characteristic of an ideal black body, which does not reflect or transmit any radiation.Rate this question:
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- 32.
Light year is unit of:
- A.
Time
- B.
Speed of light
- C.
Distance
- D.
Mass
Correct Answer
C. DistanceExplanation
A light year is a unit of distance, not time, speed of light, or mass. It is defined as the distance that light travels in one year in a vacuum. Since light travels at a constant speed, this distance is approximately 9.46 trillion kilometers or 5.88 trillion miles. Therefore, the correct answer is distance.Rate this question:
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- 33.
Permanent magnet can be made from
- A.
Cobalt
- B.
Aluminium
- C.
Zinc
- D.
Lead
Correct Answer
A. CobaltExplanation
Permanent magnets can be made from cobalt because cobalt is a ferromagnetic material, meaning it has a high magnetic permeability and can retain a strong magnetic field. When cobalt is magnetized, it can maintain its magnetism over a long period of time, making it suitable for use in permanent magnets. Aluminium, zinc, and lead are not suitable for making permanent magnets as they are not naturally magnetic materials.Rate this question:
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- 34.
Compton effect is associated with
- A.
Positive rays
- B.
B-rays
- C.
X-rays
- D.
None of these
Correct Answer
C. X-raysExplanation
The Compton effect is associated with x-rays. This effect refers to the scattering of x-ray photons by electrons, resulting in a change in the wavelength of the scattered photons. This phenomenon provided evidence for the particle-like behavior of photons and supported the concept of photons having both wave and particle properties. The Compton effect is an important phenomenon in the field of quantum mechanics and has applications in various fields, including medical imaging and materials science.Rate this question:
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- 35.
The forward voltage drop across a silicon diode is about
- A.
2.5 V
- B.
3 V
- C.
10 V
- D.
0.7 V
Correct Answer
D. 0.7 VExplanation
The forward voltage drop across a silicon diode is typically around 0.7 V. This is because silicon diodes have a forward voltage drop of approximately 0.7 V when they are conducting current in the forward direction. This characteristic is important in many electronic circuits as it allows the diode to act as a one-way valve for current flow.Rate this question:
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- 36.
The leakage current in a crystal diode is due to …………….
- A.
Minority carriers
- B.
Majority carriers
- C.
Junction capacitance
- D.
None of the above
Correct Answer
A. Minority carriersExplanation
The leakage current in a crystal diode is due to minority carriers. In a diode, there are two types of carriers: majority carriers and minority carriers. Majority carriers are the dominant carriers in the diode, while minority carriers are present in smaller numbers. When a diode is reverse biased, a small amount of current called leakage current flows, primarily due to the movement of minority carriers across the junction. This leakage current is typically very low, but it is important to consider in certain applications where precise current control is required.Rate this question:
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- 37.
Which instrument is used to measure sound under water ?
- A.
Hygrometer
- B.
Hygroscope
- C.
Hypsometer
- D.
Hydrophone
Correct Answer
D. HydrophoneExplanation
A hydrophone is an instrument specifically designed to measure sound underwater. It is used to detect and record underwater sounds, including those produced by marine animals, ships, and submarines. Hydrophones are widely used in various fields such as marine biology, oceanography, and underwater acoustics research. They are typically made up of a waterproof microphone that converts sound waves into electrical signals, which can be analyzed and interpreted by scientists and researchers.Rate this question:
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- 38.
Which instrument is used to measure pressure of gases ?
- A.
Manometer
- B.
Machmeter
- C.
Magnetometer
- D.
Micrometer
Correct Answer
A. ManometerExplanation
A manometer is used to measure the pressure of gases. It consists of a U-shaped tube filled with a liquid, usually mercury or water. One end of the tube is connected to the gas source, and the other end is open to the atmosphere. The difference in height of the liquid in the two arms of the tube indicates the pressure of the gas being measured. Manometers are commonly used in various industries, laboratories, and engineering applications to accurately measure and monitor gas pressure.Rate this question:
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- 39.
Which instrument is used to measure heat radiation ?
- A.
Radar
- B.
Salinometer
- C.
Refractometer
- D.
Radio micrometer
Correct Answer
D. Radio micrometerExplanation
A radio micrometer is an instrument used to measure heat radiation. It measures the intensity of electromagnetic radiation in the radio frequency range, which includes heat radiation. This instrument is commonly used in scientific research and industrial applications to measure and study heat radiation emitted by various sources.Rate this question:
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- 40.
Which instrument is used to measure strength of direct current ?
- A.
Stroboscope
- B.
Streoscope
- C.
Tangent Galvanometer
- D.
Tachometer
Correct Answer
C. Tangent GalvanometerExplanation
A tangent galvanometer is an instrument used to measure the strength of a direct current. It works based on the principle of the tangent law, which states that the tangent of the angle of deflection of a magnetic needle is directly proportional to the strength of the current passing through the coil. By measuring the angle of deflection, the strength of the current can be determined. Therefore, a tangent galvanometer is the correct instrument for measuring the strength of direct current.Rate this question:
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- 41.
K. Macmillan invented
- A.
Bicycle
- B.
Barometer
- C.
Calculating Machine
- D.
Centigrade Scale
Correct Answer
A. BicycleExplanation
K. Macmillan is credited with inventing the bicycle. The other options listed, such as the barometer, calculating machine, and centigrade scale, were not invented by K. Macmillan.Rate this question:
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- 42.
David Hughes invented
- A.
Machine Gun
- B.
Microphone
- C.
Microscope
- D.
Motorcycle
Correct Answer
B. MicrophoneExplanation
The correct answer is Microphone. David Hughes is known for his invention of the microphone. A microphone is a device that converts sound waves into electrical signals, allowing for the amplification and recording of audio. It is widely used in various applications such as telecommunication, broadcasting, and recording industries.Rate this question:
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- 43.
The gas used for artificial fruit ripening of green fruit is —
- A.
Ethylene
- B.
Acetylene
- C.
Ethane
- D.
Methane
Correct Answer
A. EthyleneExplanation
Ethylene is the gas used for artificial fruit ripening of green fruit. Ethylene is a plant hormone that plays a crucial role in the ripening process. When green fruits are exposed to ethylene, it triggers a series of physiological changes, including the breakdown of chlorophyll and the conversion of starches into sugars. This process leads to the softening, sweetening, and color development of the fruit, making it appear ripe. Therefore, ethylene is commonly used in the food industry to accelerate the ripening of fruits and ensure they are ready for consumption.Rate this question:
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- 44.
The three elements most needed in common fertilisers are :
- A.
Sulphur, Phosphorous and sodium
- B.
Nitrogen, Potassium and Phosphorous
- C.
Phosphorous, Sodium and Nitrogen
- D.
Calcium, Phosphorous and Potassium
Correct Answer
B. Nitrogen, Potassium and PhosphorousExplanation
The three elements most needed in common fertilizers are nitrogen, potassium, and phosphorous. These three elements are essential for plant growth and development. Nitrogen is important for leaf and stem growth, potassium helps with overall plant health and disease resistance, and phosphorous is crucial for root development and flower/fruit production.Rate this question:
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- 45.
Which one of the following metals pollutes the air of a city having large number of automobiles?
- A.
Cadmium
- B.
Chromium
- C.
Lead
- D.
Copper
Correct Answer
C. LeadExplanation
Lead is the correct answer because it is commonly found in gasoline and is released into the air when vehicles burn fuel. This pollution can lead to various health problems when inhaled, such as respiratory issues and neurological damage. Lead pollution from automobiles is a significant concern in cities with high traffic levels, making it the metal that pollutes the air in such areas.Rate this question:
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- 46.
What is the chemical name for ‘baking soda’?
- A.
Sodium carbonate
- B.
Sodium bicarbonate
- C.
Sodium nitrite
- D.
Sodium nitrate
Correct Answer
B. Sodium bicarbonateExplanation
Baking soda is commonly known as sodium bicarbonate. It is a chemical compound that is often used in baking as a leavening agent. When it is combined with an acid, such as vinegar or lemon juice, it produces carbon dioxide gas, which helps dough or batter rise. Sodium carbonate, sodium nitrite, and sodium nitrate are different chemical compounds and not the correct chemical name for baking soda.Rate this question:
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- 47.
An atomic pile is used for
- A.
Producing X-rays
- B.
Conducting nuclear fission
- C.
Coducting thermonuclear fusion
- D.
Accelerating atoms
Correct Answer
B. Conducting nuclear fissionExplanation
An atomic pile is a device that is specifically designed for conducting nuclear fission. Nuclear fission is the process in which the nucleus of an atom is split into two smaller nuclei, releasing a large amount of energy. Atomic piles use controlled nuclear fission reactions to generate heat, which can then be used to produce electricity or for other purposes. Therefore, conducting nuclear fission is the correct answer as it accurately describes the main purpose of an atomic pile.Rate this question:
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- 48.
Which of the following gases is present under pressure in soft drinks?
- A.
Oxygen
- B.
Nitrogen
- C.
Carbon dioxide
- D.
Nitrous oxide
Correct Answer
C. Carbon dioxideExplanation
Carbon dioxide is present under pressure in soft drinks because it is used to carbonate the beverages. When carbon dioxide is dissolved in water, it creates carbonic acid, which gives the drinks their characteristic fizz. The pressure keeps the carbon dioxide dissolved in the liquid until the bottle or can is opened, at which point the gas is released and creates the bubbles in the drink.Rate this question:
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- 49.
The substance which does not expand on going from liquid state to solid state is
- A.
Water
- B.
Cast-iron
- C.
Aluminium
- D.
Type metal
Correct Answer
D. Type metalExplanation
Type metal is an alloy that is used for making printing typefaces and other high-quality printing plates. It is composed of a mixture of lead, antimony, and tin. Unlike water, cast-iron, and aluminum, type metal does not expand when it goes from a liquid state to a solid state. This is because the specific composition of type metal allows it to have a low coefficient of thermal expansion, meaning it does not significantly change in volume when it solidifies.Rate this question:
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- 50.
The radio-active element used in heart pacemakers is
- A.
Uranium
- B.
Deuterium
- C.
Plutonium
- D.
Radium
Correct Answer
C. PlutoniumExplanation
Plutonium is the correct answer because it is a radioactive element that is commonly used in heart pacemakers. It is chosen for its unique properties, including its ability to generate a steady stream of energy through the process of radioactive decay. This energy is then used to power the pacemaker and regulate the heartbeat of the patient. Plutonium is preferred over other radioactive elements due to its long half-life and high energy output, making it suitable for long-term use in medical devices.Rate this question:
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