All questions of Practice Tests for BPSC (Bihar) Exam

Answer is a And c

The Beaufort Scale. The Beaufort Scale or Beaufort Wind Force Scale is a system for estimating wind strengths without the use of instruments, based on the effects wind has on the physical environment. The scale was devised in 1805 by the British naval Commander, later Admiral, Sir Francis Beaufort 

Cataract

(Correct Option:- C, Magnetic Field)

A tape is coated with tiny magnetic particles. These particles get magnetized, when electric signal passes through them. Thus, a tape recorder records sound in the form of magnetic field on the tape.

The answer is B because the Earth's gravity's effect. If the gravity quotient is low, the satellite won't orbit the Earth, henceforth the period of revolution is zero.

The epidemic bone-softening disease, ItaiItai, occurred in Japan as a result of the presence of cadmium in the environment. Here is a detailed explanation of why Japan was the location of this disease outbreak:

1. Background:
ItaiItai disease is a condition caused by long-term exposure to high levels of cadmium, a heavy metal that can contaminate water, soil, and food. Cadmium is released into the environment through various industrial activities, including mining, battery production, and waste incineration. It is also present in phosphate fertilizers, which were extensively used in Japan's agricultural practices.

2. Geography and Industrialization:
Japan, known for its rapid industrialization in the 20th century, experienced significant pollution and environmental degradation during this period. The country's numerous mining activities, industrial plants, and manufacturing processes contributed to the release of cadmium into the environment. Additionally, Japan's geography, with its mountainous terrain and numerous river systems, facilitated the spread of cadmium-contaminated water across regions.

3. Toyama Prefecture:
The most severely affected region by ItaiItai disease was the Toyama Prefecture, located in central Japan. The Jinzu River, which flows through the prefecture, had been contaminated with cadmium due to mining activities in the upstream areas. The polluted water from the river was used for irrigation and drinking purposes, leading to widespread cadmium exposure among the local population.

4. Agricultural Practices:
Agriculture plays a crucial role in Japanese society, and the extensive use of phosphate fertilizers containing cadmium further exacerbated the problem. The contaminated fertilizers were applied to rice paddies, resulting in the accumulation of cadmium in the soil and subsequent uptake by crops. As a staple food, rice became a significant source of cadmium exposure for the population.

5. Symptoms and Impact:
ItaiItai disease primarily affected women, particularly postmenopausal women, who had been exposed to high levels of cadmium over many years. The disease is characterized by severe pain in the bones and joints, leading to a reduction in mobility and overall quality of life. Other symptoms include anemia, kidney damage, and weakened immune system. The widespread occurrence of this debilitating disease had a significant social and economic impact on the affected communities.

6. Government Response:
The outbreak of ItaiItai disease drew attention to the hazardous effects of cadmium pollution, prompting the Japanese government to take action. Measures were implemented to reduce cadmium emissions and improve wastewater treatment in industrial facilities. Additionally, stricter regulations were introduced regarding the use of cadmium-containing fertilizers in agriculture.

In conclusion, the epidemic bone-softening disease, ItaiItai, occurred in Japan due to the presence of cadmium in the environment. The combination of industrial activities, agricultural practices, and geographical factors contributed to the contamination of water, soil, and food sources with cadmium. The disease outbreak, particularly severe in the Toyama Prefecture, highlighted the detrimental effects of cadmium exposure and led to government interventions to mitigate future occurrences.

During a cow's digestion process, they release an approximated 75 percent of the methane gas released by animals. Cows release so much methane because of the bacteria in the cow's multiple stomachs. The bacteria allows the cows to better process their food.

When the angle of incidence in a denser medium is equal to the critical angle, the angle of refraction is 90 degrees (or pi/2 radians) and the refracted ray travels along the boundary between the two media. This phenomenon is known as total internal reflection.

It's possible to convert all plastics directly into useful forms of energy and chemicals for industry, using a process called "cold plasma pyrolysis". Pyrolysis is a method of heating, which decomposes organic materials at temperatures between 400degreeC and 650 degreeC, in an environment with limited oxygen.

Decay of Radioactive Waste in a Light Water Nuclear Reactor

Radioactive waste products from a light water nuclear reactor can remain deadly for a significant amount of time due to their long half-lives. The process through which these waste products lose their deadly radiation is known as radioactive decay.

Factors Affecting Decay Time

- The type of radioactive isotopes present in the waste
- The half-life of these isotopes

Radioactive Isotopes in Light Water Reactor Waste

- Common isotopes include cesium-137 and strontium-90
- Both have long half-lives contributing to the longevity of the radiation

Half-Life of Radioactive Isotopes

- Cesium-137 has a half-life of about 30 years
- Strontium-90 has a half-life of about 28 years

Practical Decay of Radioactive Waste

- To practically lose their deadly radiation, radioactive waste products from a light water nuclear reactor may take up to hundreds of years.
- In this case, it would take approximately 700 years for the radioactive waste to reach safe levels of radiation.

Therefore, option c) 700 years is the correct answer as it aligns with the time needed for the decay of radioactive waste from a light water nuclear reactor to become less harmful.

Excessive inhalation of manganese can cause pneumonia.

Pneumonia is a lung infection that can be caused by various factors, including exposure to certain chemicals and substances. Manganese is a naturally occurring element found in the Earth's crust. It is commonly used in industrial processes, such as iron and steel production, welding, and battery manufacturing.

Excessive inhalation of manganese particles can occur in occupational settings where workers are exposed to high levels of airborne manganese dust or fumes. When inhaled, manganese particles can enter the lungs and cause inflammation and damage to the respiratory system. This can lead to the development of pneumonia.

Pneumonia is characterized by the inflammation of the air sacs in the lungs, which may fill with fluid or pus. Common symptoms of pneumonia include cough, chest pain, fever, difficulty breathing, and fatigue. In severe cases, pneumonia can be life-threatening, especially for individuals with weakened immune systems or pre-existing respiratory conditions.

In the case of excessive inhalation of manganese, the metal particles can irritate and damage the delicate tissues of the lungs. This can impair the normal functioning of the respiratory system and increase the risk of developing pneumonia. Prolonged exposure to high levels of manganese can also lead to the accumulation of the metal in the lungs, further exacerbating the damage and inflammation.

It is important to note that the risk of developing manganese-induced pneumonia is primarily associated with occupational exposure rather than environmental exposure. Occupational safety measures, such as the use of personal protective equipment and proper ventilation systems, are essential in minimizing the risk of inhalation of manganese particles.

In conclusion, excessive inhalation of manganese can cause pneumonia. Occupational exposure to high levels of manganese dust or fumes can lead to lung inflammation and damage, increasing the risk of developing pneumonia. Proper safety measures should be implemented in industrial settings to prevent excessive exposure to manganese and protect workers from respiratory health hazards.

Fly ash from thermal power plants - Waste management and overview. Energy requirements for the developing countries in particular are met from coal-based thermal power plants. ... In India, nearly 90 mt of fly ash is generated per annum at present and is largely responsible for environmental pollution.

SONAR: The Technique Employed at Sea to Detect and Determine the Position of Underwater Objects and Sea Depth

Introduction:
One of the key challenges in maritime operations is the detection and tracking of underwater objects and determining the sea depth accurately. To overcome this challenge, the technique of SONAR (Sound Navigation and Ranging) is employed extensively in the maritime domain. SONAR uses sound waves to detect and locate underwater objects and measure the depth of the sea.

Working Principle:
SONAR works on the principle of echo sounding. It involves emitting sound waves into the water and measuring the time it takes for the waves to bounce back after hitting an object. Based on the speed of sound in water and the time taken for the echo to return, the distance to the object can be calculated.

Components and Operation:
SONAR systems consist of three main components:
1. Transmitter: It generates and emits sound waves into the water.
2. Receiver: It captures the echoes of the sound waves returning from underwater objects.
3. Display Unit: It processes the received signals and presents the information in a usable format.

The transmitter emits a short burst of sound waves, usually in the ultrasonic frequency range. These waves travel through the water and when they encounter an object, they bounce back as echoes. The receiver captures these echoes, and the time taken for the echo to return is recorded. Using the speed of sound in water, which is known, the distance to the object can be calculated.

Applications:
SONAR has various applications in the maritime domain, including:
1. Navigation and Mapping: SONAR is used to determine the depth of the sea, locate underwater obstacles like rocks and wrecks, and create accurate depth charts for safe navigation.
2. Submarine Detection: SONAR is vital for detecting and tracking submarines underwater. It helps in maintaining maritime security and preventing unauthorized intrusion.
3. Fisheries: SONAR is used in fish finding and stock assessment. It helps fishermen locate fish schools and estimate their abundance, enabling sustainable fishing practices.
4. Underwater Research: SONAR is used in scientific research to study underwater ecosystems, map the seabed, and investigate geological features.

Conclusion:
SONAR is a crucial technique employed at sea to detect and determine the position of underwater objects and measure sea depth accurately. It has revolutionized maritime operations by enabling safe navigation, submarine detection, fisheries management, and underwater research. SONAR systems continue to evolve, incorporating advanced technologies to enhance their detection capabilities and improve the accuracy of measurements.

A Geiger counter, or a Geiger-Muller tube, is used for detecting and measuring alpha, beta and gamma radiation. It consists of a pair of electrodes with a high voltage running between them. These electrodes are surrounded by a gas, usually argon or helium. Radiation entering the tube ionizes the gas

Discussing step by step
First we know that x rays are produced by high speed e when bombarded at metal surface, now cathode rays carry electrons (CATHODE IS POSITIVE ELECTRODE BUT CATHODE RAYS CARRY ELECRONS). It is correct...
Going on third option, choke coil is used in ac only because for ac we have some value of reactance as w is not equal to zero... For dc reactance becomes zero hence no use...
Also u know that gamma rays are neutral rays so no deflection....
For second option I am not sure, i think no effect will be there bcoz speed of light is far more greater than speed of object producing it..... I think it will have some effect when object moves with a large speed....

Electromagnetic waves consist of infrared waves...

Ozone is used for disinfecting the air in underground railways.

Explanation:
• Underground railways are confined spaces where air circulation is limited. This often leads to poor air quality and the accumulation of harmful pollutants.
• To prevent the spread of diseases and ensure good air quality, disinfection of the air in underground railways is necessary.
• Ozone is a powerful oxidizing agent and is known to kill bacteria, viruses, and other microorganisms. It is also effective in removing odors and other pollutants from the air.
• Ozone generators are installed in underground railways to produce ozone gas, which is then circulated through the ventilation system to disinfect the air.
• Ozone is preferred over other disinfectants like chlorine as it does not leave any harmful residues and is safe for human exposure at low concentrations.
• However, ozone should be used with caution as it can be harmful to human health at high concentrations. Therefore, proper monitoring and control of ozone levels are necessary in underground railways.

The infrasonic waves are produced by large vibrating bodies. These waves are not audible to a human ear. For example, infrasonic waves are produced by the vibration of the earth's surface during the earthquake.

C

The faster an organ's cells dividing, more vulnerable it is to radiation.This is the basis of radiotherapy for malignancy, because malignant cells divide extremely fast in comparison to normal cells;Which organs have the most cell divisions? Bone marrow (continuously producing blood cells) and digestive tract (replacing the mucosa that's dying in contact with food and digesting enzymes).So bone marrow and digestive system are the first organs affected by the radiation. bone marrow suppression takes time to show its manifestations and this is why gastrointestinal symptoms (vomiting) are among the first symptoms of radiation sickness.

C. option is correct
Remain unchanged

Explanation:

Mutagens are agents that can cause mutations, which are changes in the DNA sequence of an organism. Mutations can occur spontaneously or be induced by exposure to certain chemicals or radiation. In this question, we are asked to identify which of the listed chemicals is a mutagen or mutation-causing agent.

Chlorinated Hydrocarbons:
Chlorinated hydrocarbons are a group of chemicals that contain carbon, hydrogen, and chlorine atoms. They are commonly used as solvents, pesticides, and industrial chemicals. Some examples of chlorinated hydrocarbons are dichloromethane, trichloroethylene, and chloroform. These chemicals have been found to be mutagenic in various studies. They can cause mutations in DNA by directly damaging the DNA molecule or by interfering with the DNA replication process.

Epoxy Resins:
Epoxy resins are a type of synthetic polymer that is commonly used in adhesives, coatings, and composite materials. They are made by combining epoxy monomers with a curing agent. While epoxy resins themselves are not mutagenic, some of the curing agents used with epoxy resins, such as amines, have been found to be mutagenic. Therefore, it is important to handle and use epoxy resins with proper safety precautions to minimize exposure to mutagenic agents.

Nitrogen Oxides:
Nitrogen oxides are a group of gases that are produced during combustion processes, such as in car engines and power plants. They are known to contribute to air pollution and can have harmful effects on human health. While nitrogen oxides can cause oxidative stress and inflammation in the body, there is limited evidence to suggest that they are mutagenic in humans.

Organophosphates:
Organophosphates are a group of chemicals that are commonly used as pesticides and insecticides. They work by inhibiting the activity of an enzyme called acetylcholinesterase, which is important for proper nervous system function. While organophosphates can have toxic effects on the body, including neurotoxicity, there is limited evidence to suggest that they are mutagenic.

Conclusion:
Based on the information provided, the correct answer is option 'A' - Chlorinated hydrocarbons. Chlorinated hydrocarbons have been found to be mutagenic and can cause mutations in DNA. However, it is important to note that the mutagenic effects of these chemicals can vary depending on factors such as the specific compound, dose, and duration of exposure. It is always advisable to follow proper safety precautions and minimize exposure to mutagenic agents to reduce the risk of mutations and associated health effects.

Explanation:
Kwashiorkor is the disease that occurs in one-to-four-year-old children from a protein-deficient diet. Here is a detailed explanation of the answer:

1. Kwashiorkor:
- Kwashiorkor is a form of severe protein-energy malnutrition that occurs due to a deficiency of protein in the diet.
- It commonly affects children aged one to four years who consume a diet low in protein but relatively high in carbohydrates.
- The main cause of Kwashiorkor is an inadequate intake of protein, which is essential for the growth and maintenance of body tissues.
- Symptoms of Kwashiorkor include edema (swelling) in the legs, feet, and abdomen, poor growth, muscle wasting, skin changes, hair changes, and weakened immune system.

2. Other Diseases:
- The other diseases listed in the options, namely Whooping Cough, Diphtheria, and Tetanus, are not directly caused by protein deficiency.
- Whooping Cough (pertussis) is a highly contagious respiratory infection caused by the bacterium Bordetella pertussis.
- Diphtheria is an infectious disease caused by the bacterium Corynebacterium diphtheriae, which primarily affects the throat and nose.
- Tetanus is a serious bacterial infection caused by the bacterium Clostridium tetani, which enters the body through open wounds.

Conclusion:
Among the given options, Kwashiorkor is the only disease that occurs in one-to-four-year-old children from a protein-deficient diet. The other listed diseases, namely Whooping Cough, Diphtheria, and Tetanus, are caused by different bacteria and are not directly related to protein deficiency.

Introduction:
The fatal brain disease that affected people eating fish caught around Minamata off the Japanese island Kyushu was caused by the metal mercury. This incident, known as the Minamata disease, is one of the most well-known cases of industrial pollution and its devastating effects on human health.

Explanation:
The Minamata disease was caused by the release of methylmercury into the environment by a chemical factory owned by the Chisso Corporation. The factory was producing acetaldehyde, a chemical used in the production of plastics, and was discharging its waste into Minamata Bay. The methylmercury present in the waste bioaccumulated in the fish and shellfish in the bay, which were then consumed by the local population.

Key Points:
- Methylmercury is a highly toxic form of mercury that can accumulate in the tissues of organisms, particularly in the fatty tissues of fish.
- When humans consume fish contaminated with methylmercury, it can be absorbed into their bloodstream and accumulate in their organs, including the brain.
- The symptoms of Minamata disease include neurological disorders such as numbness, muscle weakness, impaired vision and hearing, and in severe cases, paralysis, coma, and death.
- The disease was first recognized in the 1950s when local fishermen and their families began experiencing these symptoms.
- The Minamata disease outbreak led to significant public health and environmental concerns and highlighted the dangers of industrial pollution and the need for stricter regulations to protect both human health and the environment.
- The incident also led to the establishment of the Minamata Convention on Mercury, an international treaty aimed at protecting human health and the environment from the adverse effects of mercury.

Conclusion:
The Minamata disease was caused by the release of methylmercury into the environment by a chemical factory, which contaminated the fish and shellfish in Minamata Bay. The consumption of these contaminated seafood led to the development of a fatal brain disease in the local population. This incident serves as a reminder of the importance of environmental regulations and the need to protect human health from industrial pollution.

A polygraph, popularly referred to as a lie detector test, is a device or procedure that measures and records several physiological indicators such as blood pressure, pulse, respiration, and skin conductivity while a person is asked and answers a series of questions.

I. In order to convert a galvanometer into an ammeter, a small resistance must be connected in parallel with the galvanometer's coil.

This statement is true because a galvanometer is a device used to measure small electric currents, while an ammeter is used to measure larger currents. To convert a galvanometer into an ammeter, a small resistance called a shunt must be connected in parallel with the galvanometer's coil. The shunt diverts a portion of the current away from the galvanometer, allowing it to measure the remaining current accurately.

II. If the diameter of a wire is reduced to half its previous value, then its resistance will increase four times.

This statement is true because resistance is inversely proportional to the cross-sectional area of a wire. The cross-sectional area of a wire is directly proportional to the square of its diameter. So, if the diameter of a wire is reduced to half its previous value, the cross-sectional area will be reduced to one-fourth of its original value. Since resistance is inversely proportional to the cross-sectional area, the resistance will increase four times.

III. During charging of a lead accumulator, the density of sulfuric acid in the accumulator increases.

This statement is true because a lead-acid battery, also known as a lead accumulator, consists of electrodes immersed in a sulfuric acid solution. During the charging process, electrical energy is converted into chemical energy, causing the lead plates in the battery to undergo a chemical reaction and convert to lead sulfate. This reaction results in an increase in the density of sulfuric acid in the accumulator.

IV. In the electrolysis of water, oxygen is given off at the cathode.

This statement is false. In the electrolysis of water, water molecules are split into hydrogen and oxygen gas using an electric current. At the cathode (negative electrode), hydrogen gas is given off, while at the anode (positive electrode), oxygen gas is given off. So, the correct statement would be that oxygen is given off at the anode, not the cathode.

Based on the explanations provided, the correct answer is option 'D' - I, II, and III.

The chloroplast is a double membrane-bound structure that contains the photosynthetic pigment chlorophyll. The photosynthetic pigments are located in the thylakoid membrane of the chloroplast. So, the correct answer is C) Chloroplast.