Bihar STET Paper 1 Science Mock Test - 8 - Bihar PGT/TGT/PRT MCQ

The ability of the eye to adjust its focal length is known as accommodation. Since, a nearby object is typically focused at a further distance,the eye accommodates by assuming a lens shape that has shorter focal length.

Burning of candle is both physical and chemical change. When the candle burns, the wax slowly melts which freezes after some time (Physical change).Burning of wick is a chemical change as it involves combustion.

22 carat gold is a homogeneous mixture in which gold is mixed with small amount of copper or silver.

Oil Yielding Plant:
Explanation:
Among the given options, the oil yielding plant is Sunflower. Here's why:
- Lentil: Lentil is a type of legume that is primarily cultivated for its edible seeds. It is not an oil yielding plant.
- Sunflower: Sunflower is a well-known oil yielding plant. The seeds of the sunflower plant are rich in oil and are commonly used for oil extraction.
- Cauliflower: Cauliflower is a vegetable that belongs to the Brassicaceae family. It does not produce oil.
- Hibiscus: Hibiscus is a flowering plant that is cultivated for its ornamental flowers. It is not an oil yielding plant.
In conclusion, among the given options, Sunflower is the oil yielding plant.

Hug the trees movement:
The "Hug the trees movement" was a grass-root level effort that aimed to end the alienation of people from their forests. The movement sought to create awareness and promote the conservation of forests by emphasizing the importance of trees and their preservation. Here is a detailed explanation:
1. Grass-root level effort:
- The movement was initiated at the grassroots level, meaning it was driven by the local communities and individuals who were directly affected by deforestation and environmental degradation.
- It was a collective effort of people who recognized the need to protect and preserve forests for the well-being of both humans and the environment.
2. Ending alienation from forests:
- The movement aimed to address the growing disconnect between people and forests.
- It sought to reconnect individuals with nature and raise awareness about the significance of forests in terms of biodiversity, ecological balance, and the provision of ecosystem services.
3. Conservation and preservation:
- The movement encouraged the conservation and preservation of forests, highlighting the role of trees in improving the quality of soil and sources of water.
- Forests play a crucial role in maintaining soil fertility, preventing erosion, and acting as natural water catchment areas.
- By hugging the trees, people displayed their love and concern for these vital natural resources.
Therefore, the "Hug the trees movement" primarily aimed to end the alienation of people from their forests and promote the conservation and preservation of these valuable ecosystems.

When a base reacts with an acid, the primary outcome is the formation of salt and water. This reaction is a fundamental property of bases and acids when they neutralize each other's properties. The formation of salt and water signifies the completion of the chemical reaction between the acidic and basic components, resulting in a more stable and neutralized solution.

Cellulose is present in cell walls of all plants, and some bacteria, and is the most abundant natural polysaccharide on earth.

The first controlled fission of an atom was carried out in Germany in 1938. Nuclear fission is the splitting of the nucleus of the atom.

Sodium aluminate and hydrogen gas are formed when sodium hydroxide reacts with aluminium metal.
2NaOH + 2Al + 2H₂O ⇨ 2NaAlO₂ + 2H₂

The excretory system in humans includes kidneys, ureters, bladder, and urethra.

Air is mixture and no energy change occurs during mixing of air. Cesium and gallium are liquid at room temperature. Pure substance have fixed melting and boiling points. Mixture is not a single substance.

Atoms of different elements with different atomic numbers and the same mass number are known as isobars. 

Fresh water and marine fisheries are found in ponds, tanks, rivers and various water bodies catla, rohu, mullets, and bhetki are some fresh water fisheries. They have important contribution to the growth of the economy of the country. There has been a very impressive growth in fish production during 1990's in the country.

The solution of Alcohol and water is miscible. Alcohol and water can be separated by the process of fractional distillation due to difference in boiling point of two liquids.

Answer:
The use of forests is diverse and provides numerous benefits to society and the environment. However, one of the following options is not an actual use of forests. Let's analyze each option in detail:
A: Controls floods
Forests play a crucial role in controlling floods by absorbing excess water and reducing runoff. The roots of trees help to stabilize soil, preventing erosion and maintaining the water-holding capacity of the land.
B: Used to make paper
Forests are commonly used as a source of raw material for the production of paper. Trees are harvested and processed to obtain pulp, which is then used in the papermaking industry.
C: Causes soil erosion
This statement is incorrect. Forests actually help prevent soil erosion due to their dense vegetation and root systems that hold the soil in place, reducing the risk of erosion caused by wind or water.
D: Resin, gum, and drugs are obtained
Forests are a valuable source of various natural products. Resin and gum are obtained from certain tree species and are used in a variety of industries. Additionally, forests may contain medicinal plants that can be used to produce drugs.
Therefore, the correct answer is C: Causes soil erosion as it does not accurately represent the benefits and uses of forests.

PHLOEM :- The structural elements of phloem include sieve tubes, companion cells, Phloem parenchyma and secretory cells. The sieve tube is the conducting element of the phloem. It is formed from a vertical series of elongated cells, interconnected by perforations in their walls in areas known as sieve plates.

Size of particles in true solutions:

• True solutions: True solutions are homogeneous mixtures of two or more substances where the solute particles are uniformly dispersed in the solvent. These particles are very small in size.


• Particle size: The size of particles in true solutions is extremely small.


• Range of particle size: The size of particles in true solutions is typically measured in nanometers (nm).


• Particle size range: The particle size of true solutions is generally less than 1 nm.


• Characteristics of true solution particles: The small size of the particles in true solutions allows them to remain dispersed and stable, without settling or separating.


• Examples of true solutions: Examples of true solutions include saltwater, sugar dissolved in water, and alcohol dissolved in water.

Therefore, the correct answer is A: < 1 nm. The size of particles in true solutions is generally less than 1 nm.

The coloured material from flower petals can be separated by chromatography process. Chromatography is used to separate materials present in solution in vary trace amount

The correct option is A.
A thermometer is an instrument that measures temperature. It can measure the temperature of a solid such as food, a liquid such as water, or a gas such as air. The three most common units of measurement for temperature are Celsius, Fahrenheit, and kelvin. The Celsius scale is part of the metric system.

The most common are nearsightedness, farsightedness, astigmatism and presbyopia. Concave and convex lenses compensate for defects in the eye, bending light rays to place them precisely on the retin and correcting vison. A concave lens is thinner in the center and thicker on the edges. Concave lenses are used in the correction for near sightedness.

When ZnO reacts with sodium hydroxide (NaOH), the resulting product is sodium zinc oxide, represented by the chemical formula Na2ZnO2. This reaction demonstrates the basic nature of metallic oxides like ZnO when they react with bases to form salts and water.

The Bowman's capsule is a cup-shaped structure at the beginning of a nephron in the kidney, which collects the filtrate from the blood capillaries.

The liver and pancreas are both exocrine and endocrine glands; they are exocrine glands because they secrete products—bile and pancreatic juice—into the gastrointestinal tract through a series of ducts, and endocrine because they secrete other substances directly into the bloodstream.

Reuse means using a product more than once, either for the same purpose (for example returnable glass milk bottles) or for a different purpose (such as old jam jars for food storage). Repairing products, selling them on or donating them to charity/community groups is also reusing!

It is preferable to recycling because the item does not need to be re-processed before it can be used again which saves both money and reduces the environmental impact.

The way in which students bring their finding to others and apply their understanding to new and unfamiliar circumstances, grows out of excitement for what they have accomplished. Student would be excited to reveal his finding.

The root to eliminate issues in the classroom is to identify the reason for a particular behaviour. Only then the issue could be resolved. The teacher must know the cause of misbehaviour, which could arise out of some confusion within the students, and the teacher then can effectively solve the problem. This also helps the teacher to make interpersonal relationship with the students, as a result of which the students confide more in their teacher.

Learning is effective in an environment that is emotionally positive and satisfying to learners. Any learner who is emotionally unstable may not be able to learn anything. The teacher must make the environment conducive for students to study and learn efficiently.
Errors made by the students do not indicate that no learning has taken place. Instead, they are the windows through which a teacher can understand the thought process of the students.
Learning is affected by emotional factors at any stage. Emotions change over time as the child matures, and in response to changing environmental interactions. The kind of learning that takes place at different emotional levels also differs.
Learning involves physical, social and emotional activity also.

An EVS teacher should accept and respect perception of children. She must respect and accept the students and their perceptions.

Given, LCM = 225, HCF = 5,
First Number = 25 , Second Number = ?
We can find the Second Number with the help of given formula,
"LCM × HCF = 1st Number× 2nd Number"
⇒ 225 × 5 = 25 × 2nd Number

∴ 2nd Number = 45

Hence, Option D is correct.