RRB JE (Railways Junior Engineer) CBT CBT 1 - Full Test 3 Free Online Test

Nephron is the basic functional unit of the kidneys. Its chief function is to regulate water and soluble substances in the blood by filtering the blood, reabsorbing what is needed.

• Glanders is an infectious disease caused through the bacterium Burkholderia Mallei.
• Glanders is primarily a disease affecting horses and donkeys.
• Glanders is spread to humans through direct contact with infected animals.
• The bacterium enters the body through cuts or scrapes in the skin and through mucosal surfaces of the eyes and nose.

Dementia is a broad category of brain diseases that is associated with a decline in memory and person's ability to perform everyday activities.

The most common type of dementia is Alzheimer's disease.

There is no known cure for dementia.

• There are 5 sense organs in a human being - Eyes, Ears, Tongue, Skin, and Nose.

• These sense organs contain receptors that relay information through sensory neurons to the appropriate places within the nervous system.

• The cerebrum is the largest part of the human brain.
• Cerebrum is the main part of the brain in humans and other vertebrates. It is located in the upper part of the cranial cavity, which is a space inside the top of the skull. cerebral cortex divided into 4 lobes

• Bryophytes is called the ‘Amphibians of Plant Kingdom’.
• These plants live in soil but they need water for sexual reproduction.
• The sperm of these plants are flagellate and need water to swim to the eggs.

• Vitamin C also known as Ascorbic acid which helps in the binding of the cells is a water-soluble vitamin and is not produced in our body.
• For a proper diet, an adequate intake of Vitamin C is important. Example- citrus fruits, broccoli, tomatoes, etc.
• Vitamins A, D, E and K are fat-soluble.

• Latent heat is the heat required for a phase change to occur without change of temperature.
• The formula for latent heat is Q = m * L   (where Q denotes the heat that must be added or removed for an object of mass (m) to change phases.)

• The washing machine works on the principle of centrifugation.
• During the wash cycle, the paddle assimilates the clothes in the soapy water.
• When the clothes are spinning in the drum, it is the centrifugal force that throws the water out through the little holes so that the washing ends up much drier.

Potential Energy : If a body develops a capacity of doing work due to its position or field, it is called the Potential energy of the body.
Potential energy decreases: The object falls vertically downwards towards the ground 

Potential energy increases: The object is lifted vertically upwards from the ground.

The orbital speed of a satellite at a height r from the centre of the earth is given by

Where M is the mass of the earth. If m is the mass of the satellite, its kinetic energy is

K = ½ mv² = ½ m GM/r

Thus K is proportional to 1/r,

Now, the time period of the satellite is given by  T =

Where R is the radius of the earth. Thus T α r^3/2

But K α 1/r

Hence K∝∝T^-2/3

A periscope is an instrument for observation over, around or through an object, obstacle or condition that prevents direct line-of-sight observation from an observer's current position. Periscopes allow a submarine when submerged at a relatively shallow depth, to search visually for nearby targets and threats on the surface of the water and in the air.

According to Kirchhoff's Radiation Law good absorbers are good emitters. For a body of any arbitrary material emitting and absorbing thermal electromagnetic radiation at every wavelength in thermodynamic equilibrium, the ratio of its emissive power is equal to a universal function only of radiative power.

The pressure inside the soap bubble is more than atmospheric pressure.

• This pressure difference is assisted by the bubble’s surface tension.
• Both surfaces of inside and outside contribute.
• The pressure difference depends on the surface tension and the bubble’s radius.
• Hence, for the same liquid, a smaller bubble can support a larger pressure difference.

• Willis Carrier invented the first modern electrical air conditioning unit in 1902.
• He later established his own company, HVAC in 1915 which specialised  in the manufacturing of heating , cooling and ventilation systems.

Cobalt-60 is used in radiation therapy because it emits gamma rays. It is produced artificially in nuclear reactors. Cobalt-60 is produced by neutron bombardment of stable cobalt in a nuclear reactor. It is used in treating cancer.

Calcium Hypochlorite is an inorganic compound with the chemical formula Ca(CIO)₂. It is known as bleaching powder as a mixture of lime and calcium chloride.

• Aqua Regia is a mixture of Nitric Acid and Hydrochloric Acid in the molar ratio of 1 ∶ 3.
• Aqua Regia is known for its ability to dissolve gold, palladium and platinum, all of which don’t react easily with chemicals.
• Aqua regia is a yellow-orange fuming liquid that has a rapidly changing composition.

• The burning of paper is an example of a chemical reaction because when it is burnt, it combines with oxygen to form smoke and ash. A chemical reaction is one that changes the chemical properties of a substance and gives off a new substance.
• A physical reaction is that which occurs when a physical change is produced through a molecular arrangement of molecules.

• The Strontium salts impart a Crimson Red colour to the fireworks.
• Strontium imparts a Crimson Red colour because when the excited atoms of Strontium contained in the salt return to the ground state it imparts electromagnetic radiation which is seen by the viewer as an emitted colour.
• Sodium imparts a yellow colour to the fireworks while barium imparts a green colour.

• The process of protecting iron by coating with Zinc is called galvanization.
• Rusting is a process of corrosion of metals.
• Metallurgy is a domain of engineering and material science that studies the chemical and physical properties of metallic elements and their alloys.

Isobars are atoms of different chemical elements that have same mass number and different atomic number.

Example:

• The arteries are the blood vessels that deliver oxygen-rich blood from the heart to the tissues of the body.
• Each artery is a muscular tube lined by smooth tissue and has three layers.

• The Sunderban Reserve Forest, the spread of 4,260 sq. km. with over 2,000 sq. km. of mangrove forests and creeks, is likely to be declared a Ramsar Site soon.
• The Indian Sunderbans, with mangrove forests, comprise almost 43% of the mangrove cover in India.
• There are currently 27 sites in India recognised as Ramsar wetland sites of international importance.

The International Union for Conservation of Nature (IUCN) Red list assigns risk categories to wild species in order to determine the threat to their existence. ‘Critically endangered’ is the highest risk category and has been assigned to more than 70 animal species and more than 60 plant species in India.

REDD stands for Reducing Emissions from Deforestation and Forest Degradation.

So in REDD, E stands for emissions.

Its objective is to mitigate climate change by reducing the emission of greenhouse gases and enhancing forest management in developing countries.

Chlorofluorocarbons (CFCs) are used as refrigerants in the vapor compression cycle to produce refrigerating and air - conditioning effects. They are a major cause of depletion of the earth’s stratospheric ozone layer and contribute to the greenhouse effect (global warming).

Eucalyptus is one of the champions of the biomass production. It lends itself particularly well to genetic environment and biotechnologies, and so to farming intensification. It is widely adopted by the international wood companies and has become the ‘Green Gold’ of pulp industry.

However, eucalyptus reduces the water table significantly in the area where it grows. Also, it reduces the fertility of the soil nearby. Hence it is considered as an ecological disaster. 

Indira Gandhi Wildlife Sanctuary and National Park (IGWLS&NP) is a protected area located in the Anaimalai Hills of Pollachi, Valparai and Udumalpet taluks of Coimbatore District and Tirupur District, Tamil Nadu state, South India.