SEE, PABSON, NPABSON Questions and Answer: Science

NATIONAL PABSAN

Pre-Board Examination-2081
Science & Technology
Time: 3hrs

Go to Top

BAGMATI PRADESH

KARNALI PRADESH

All the question are compulsory

Tick the correct alternatives.

[Group-Al

Multiple choice questions. [1x10=10]

1- Which of the following is the negative impact of digital technology?

(a) Digital library                      (b) cyber bullying

(c) Digit Payment                      (d) All

2- Which is not gymnosperm?

(a) Cycas                                  (b) Pine

(c) Coconut                               (d) Cedar

3-Chlorophyll is absent in.

(a) mushroom                            (b) moss

(c) spirogyra                             (d) Volvox

4- Why is cycas kept in gymnosperm?

(a) It bears flowers and produces seed.               (b) It bears flowers and has pointed leaf.

(c) It has cone instead of flowers and seed.         (d) It has cone instead of flower and seed is naked.

5-Which is the value of acceleration due to gravity of the earth zero?

a) At the centre                         (b) at the sea level

(c) at the equator                       (d) at poles

6-On Which principle is a lactometer based?

(a) Pascal's law                         (b) Archimedes principle

(c) Law of floatation                  (d) Newton's law

7-Which of the following is the refractive index of water?

(a) 1.36                                     (b) 1.33

(c) 1.56                                     (d) 1.47

8-Which in the most realistic theory about origin of the universe?

(a) Heliocentric theory               (b) Geocentric theory

(c) Newton's theory                   (d)Big bang

9- What is denoted by x in the given reaction?

2KClO3 ----- Xà2Kcl +302

(a) catalyst                                (b) Heat

(c) Pressure                               (d) light

10. What is the main use of detergent?

(a) taking bath                           (b) Washing clothes

(c) cleaning toilet                      (d)cleaning hands and legs

Answers

1. (b) Cyber bullying 2. (c) Coconut 3. (a) Mushroom 4.(d) It has cone instead of flower and seed is naked.

5. (a) At the centre 6. (b) Archimedes' principle 7. (b) 1.33 8.(d) Big Bang 9. (b) Heat 10. (b) Washing clothes

2-very short answer type questions.

(a) Define independent variables.
Independent variables are the variables that are deliberately changed or controlled in an experiment to observe their effect on dependent variables.

(b) State Pascal's law.
Pascal’s law states that the pressure applied to a confined fluid is transmitted undiminished in all directions throughout the fluid.

(c) Anu cannot distinguish red and green color. What is the main cause of this problem?
The main cause of this problem is color blindness, which occurs due to the absence or defect of red or green cone cells in the retina.

(d) Define power of a lens.
The power of a lens is the ability of the lens to converge or diverge light. It is measured in diopters (D) and is given by: Power (P) =

i.e. P =

 (e) Define magnetic flux.
Magnetic flux is the total number of magnetic field lines passing through a given surface.

(g) Write the main ore of iron.
The main ore of iron is Hematite (Fe₂O₃).

(h) Define roasting.
Roasting is the process of heating sulfide ores in the presence of excess air to convert them into oxides. Example: 2ZnS+3O₂→2ZnO +2SO₂

(i) Write a difference between saturated and unsaturated hydrocarbons on the basis of reactivity.
Saturated hydrocarbons (alkanes) are less reactive because they contain only single bonds.
Unsaturated hydrocarbons (alkenes and alkynes) are more reactive due to the presence of double or triple bonds, which can undergo addition reactions.

 [Group-c]

3. Why do we use the unit-wise analysis of the equation? Write two reasons.

We use unit wise analysis of the equation:

1. To verify the correctness of a given equation.
2. To ensure dimensional consistency in physical equations.

4. Write any 2 characteristics of class Amphibia.

Two characteristics of class Amphibia are:

1. They can live both in water and on land (dual habitat).
2. They have moist, glandular skin without scales.

5. Write any 2 differences between drone bee and worker bee.

Drone Bee	Worker Bee
Male bee, developed from unfertilized egg.	Female bee, developed from fertilized egg.
Its main role is mating with the queen.	Performs various tasks like collecting nectar, making honey, and protecting the hive.

6. Write down the major function of DNA and RNA.

The major function of DNA and RNA are mentioned below:

DNA (Deoxyribonucleic Acid): Stores and transmits genetic information.
RNA (Ribonucleic Acid): Helps in protein synthesis by translating genetic codes from DNA.

7. Why did Mendel select the pea plant for his experiment? Give two reasons.

Mendel select the pea plant for his experiment because of the following reasons:

1. Short life cycle – It grows and reproduces quickly.
2. Distinct traits – Pea plants have easily distinguishable characteristics like flower color and seed shape.

8. Write any 2 causes of increasing uric acid.

Two causes of increasing uric acid are:

1. Excessive consumption of protein-rich foods (e.g., red meat, seafood).
2. Reduced kidney function, leading to poor excretion of uric acid.

9. Many important plants are being extinct in Nepal due to climate change. What role can you play to protect such plants?

Roles I can play to protect important plants from being extinction due to climate change are:

1. Promote afforestation and reforestation by planting native species.
2. Spread awareness about climate change and conservation practices.

10. Write any two effects of gravity.

Two effects of gravity are:

1. It keeps planets in their orbits around the sun.
2. It causes objects to fall towards the earth.

11. Clarify the statement, "Acceleration due to gravity of the earth is 9.8 m/s²."

This means that when an object falls freely under gravity, its velocity increases by 9.8 m/s every second.

12. Write any two differences between step-up and step-down transformers.

Step-Up Transformer	Step-Down Transformer
Increases voltage	Decreases voltage
Has more turns in the secondary coil than in the primary coil	Has more turns in the primary coil than in the secondary coil

13. Draw a simple diagram of an electromagnet.

14. How does heat enhance the rate of chemical reaction? Give reason.

Heat increases the kinetic energy of molecules, causing more frequent and energetic collisions, which speeds up the reaction.

15. Write the structural formula of methyl alcohol and mention its one use.

Structural formula: CH₃OH

Use: It is used as an industrial solvent and fuel additive.

16. Write any two differences between soap and detergent.

Soap	Detergent
Made from natural oils or fats	Made from synthetic chemicals
Works best in soft water	Works in both hard and soft water

Long answer type questions: [Group-D] [7X4=28]

17. Write any two positive and negative impacts of digital technology in human life.

Positive Impacts of digital technology in human life are:

1. The internet provides vast knowledge through search engines, online courses, and e-books.
2. Social media and instant messaging allow people to stay connected globally.

Negative Impacts of digital technology in human life are:

1.  Digital technology has increased hacking, online fraud, and social media abuse.
2. Excessive screen time leads to eye strain, poor posture, and mental health issues.

18. What do you mean by endangered animals? Mention the cause of declining their number. Enlist the ways to protect them from being extinct.

The causes of declining the numbers of endangered animals are listed below:

Endangered animals are species that are at risk of extinction due to a rapid decline in their population.

a) Habitat destruction due to deforestation and urbanization.

b) Poaching and illegal wildlife trade.

c) Climate change affecting their natural habitat.

d) Pollution leading to water and air contamination.

The Ways to protect them from being extinct are listed below:

1. Establishing wildlife reserves and national parks.
2. Implementing strict anti-poaching laws.
3. Promoting conservation programs and awareness campaigns.
4. Reducing pollution and habitat destruction.

19. Draw the internal structure of the human heart and label its major parts.

20. Calculate how much heat is needed to raise the temperature of 500g of water from 50°C to 80°C.

Given:

Mass of water (m) = 500 g = 0.5 kg

Specific heat capacity of water (s) = 4200 J/kg°C

Initial temperature (T₁) = 50°C

Final temperature (T₂) = 80°C

Heat (Q) = ?

We know that;

Q=msdt

or, Q = mxsx(T₂-T₁)

or, Q = 0.5 x 4200 x (80⁰-50⁰)

or Q = 0.5 x 4200 x 30⁰

or, Q = 6300 J

or 63 KJ

21. If a student on the last bench of the class cannot read the letters written on the whiteboard clearly.

(a) Draw a diagram to show the defect of his eye.

(b) What is the cause of the defect?
 Myopia (Short-sightedness) occurs due to:

1. Elongation of the eyeball, causing light rays to focus in front of the retina.
2. Increased curvature of the lens, making it too strong to focus correctly.

(c) Which lens is used to correct this defect? Why?
 Concave lens is used because it diverges the incoming light rays, allowing the image to be focused on the retina.

22. Answer the following questions based on the electronic configurations of A and B.

Given:

• A = 1s², 2s², 2p⁶, 3s², 3p⁶, 4s¹
• B = 1s², 2s², 2p⁵

(i) In which group do elements A and B belong?
 A belongs to Group 1 (Alkali metals) → Because it has one electron in the outermost shell.
 B belongs to Group 17 (Halogens) → Because it has seven valence electrons.

(ii) Write the molecular formula of the compound formed by the combination of A and B.

The molecular formula of the compound formed by the combination of A and B is AB (NaCl)
A donates 1 electron, and B accepts 1 electron → The formula is AB (e.g., NaCl if A is sodium and B is chlorine).

(iii) Why is element B placed in the P-block of the periodic table?
Because its last electron enters the p-orbital (2p⁵).

23. Draw a well-labeled diagram of the laboratory preparation of ammonia gas and write the method to test this gas in a gas jar.

 Test for Ammonia Gas:

1. Ammonia turns red litmus paper blue because it is basic in nature.
2. Ammonia produces dense white fumes when exposed to hydrogen chloride (HCl) gas.

BAGMATI PRADESH BP

RE-1041'BP'

SEE 2081 (2025)

(Section 'A')

Multiple Choice Questions

1. Choose the best alternative to the following questions and write in the answer sheet.  10x1=10

(a) What is the number of chromosome in human skin cell?

(i) 40                   (ii) 42                  (iii) 44                               (iv) 46

(b) Which is the correct formula to find the focal length of a lens?

(i) f=M/u                          (ii) f=I/O                           (iii) f= 1/p                        (iv) f = 1/u        

(c) Which valve control the blood flow from right ventricle to right auricle?

(i) aortic valve              (ii) bicuspid valve       (iii) pulmonic valve              (iv) tricuspid valve

(d) Which medicinal plant has the antimicrobial property that can activate digestive process?

(i) Neem                                        (ii) Heart leaved moonseed

(iii) Asiatic pennywort)                (iv) Holy basil

(e) Which of the following is a di-hydric alcohol?

(i) Ethanol                      (ii) Ethylene glycol      (iii) Methanol               (iv) Glycerol)

(f) If the Earth could be squeezed to the size of the Moon, what would be the effect on the value of acceleration due to gravity of the Earth?

(i) increases                  (ii) decreases               (iii) becomes zero               (iv) remains the same

(g) Which of the following fact is correct?

(i) Electric motor changes electrical energy into kinetic energy

(ii) Electric generator changes electrical energy in to mechanical energy.

(iii) Both electric motor and generator work on same principle.

(iv) Both electric motor and generator changes mechanical energy into electrical energy

(h) On which of the following factors does specific heat capacity depend upon?

(i) mass of matter                                                  (ii) volume of matter

(iii) temperature of matter                                  (iv) nature of matter

(i) Which of the following group of fundamental units represent the derived unit of energy Joule (J)?

(i) kg ms^-2                        (ii) kg ms^-1                       (iii) kg m²s^-2                                  (iv) kg ms^-3

(j) If 500 N force is applied on the piston A, how much force is produced on piston B ?

(i) 875 N                          (ii) 975 N                         (iii) 1075 N                     (iv) 1175 N

Section 'B'

2. Write very short answers to the following questions.                 9×1=9

(a)  What is the name of the blood vessel that carries blood from heart to different parts of the body?

The name of the blood vessel that carries blood from heart to different parts of the body is artery.

(b) Write the name of compound which is formed when ammonia dissolves in water?

The name of the compound which is formed when ammonia dissolves in water is ammonium hydroxide.

(c) Why carbon dioxide gas is collected in an erect gas jar?

Carbon dioxide gas is collected in an erect gas jar because it is heavier than air.

(d) Write a precaution to be taken by a good netizen.

A precaution to be taken by a good netizen is:
Not to share personal information like passwords,  address, or financial details on public platforms or with untrusted sources.

(e) What change does a negative catalyst do in the rate of chemical reaction?

A negative catalyst slow down the rate of chemical reaction without going any change in itself.

(f) Why is detergent considered less eco-friendly than soap? Give one reason.

Detergent is considered less eco-friendly than soap because it is non-biodegradable, it does not break down easily in nature and pollute the water bodies.

(g) When black (Bb) and brown (bb) dog are crossed, what is the genotypic ratio at second filial generation?

When black (Bb) and brown (bb) dog are crossed

1. In first fillial generation: Bb × bb
• F₁ generation genotypes: Bb and bb → 1:1 ratio
2. In second filial generation F₂ generation (cross Bb × bb)
• Using Punnett square:

	B	b
b	Bb	bb
b	Bb	bb

Genotypes:

• Bb: 2
• bb: 2

 

(h) A student has faced difficulties in reading letters on the board from last bench due to a defect of vision. Draw a ray diagram of remedy of the problem of that person.

The student is suffering from myopia (short sightedness). The ray diagram of remedy of the problem is shown below:

(i) Calculate the refractive index of water, if speed of light in water is 2.25×105 m/s and in air is 3×108 m/s.

Given:

• Speed of light in water = 2.25×10⁸ m/s
• Speed of light in air (vacuum) = 3×10⁸ m/s,

Refractive index (µ) =           

µ=   

=1.33

Write short answers to the following questions: (14×2=28)

3. Write any two characteristics of worker bee.

Two characteristics of worker bees are:

(i) Worker bees are sterile female bees that cannot reproduce.

(ii) They perform all essential duties in the hive, such as foraging for nectar, feeding larvae, and cleaning the hive.

4. Mention any two effects of climate change.

Two effects of climate change are:

(i) Increase in frequency and intensity of natural disasters like floods and droughts.

(ii) Rise in global temperature, leading to climate change.

5. Write two differences between independent and dependent variables.

Independent Variable	Dependent Variable
(i) It is controlled or changed in an experiment.	(i) It is observed and measured during the experiment.
(ii) It is the presumed cause.	(ii) It is the effect or outcome being studied.

6. Write class of sparrow and division of fern.

Class of sparrow: Aves

Division of fern: Pteridophyta

7. What difficulties would Mendel have faced if he had used apple plant instead of pea for his experiment? Write in two points.

(i) Apple plants take many years to grow and produce offspring, delaying results.

(ii) Apples have complex inheritance patterns and fewer contrasting traits than pea plants.

8. In the given figure, what does 16 N represent? What should be the weight of the object to float on the water?

In the given figure 16 N represent the upthrust on the object. The weight of the object should be 16 Newton in order to float on water, This is because floating object displaces liquid equal to their own weight.

9, Differentiate between the flat universe and closed universe in two points.

Flat Universe	Closed Universe
i) The universe has zero curvature (like a flat sheet); parallel lines never meet.	(i) The universe has positive curvature (like a sphere); parallel lines eventually meet.
(ii) It will expand forever at a decreasing rate but never collapse.	(ii) It will eventually stop expanding and start contracting (Big Crunch).

 

10. Answer the questions on the basis of given chemical equations.

Reaction A: MgO + H₂O àMg(OH)₂

Reaction B: Zn + dil H₂SO₄ à ZnSO₄ + H₂

(i) Out of these two chemical equations, which one is the combination reaction?

Out of these chemical equation the reaction number a is combination reaction,

(ii) What happens when conc. H SO₄ is used instead of dil H₂SO₄ in chemical reaction B?

When conc. H SO₄  is used instead of dil H₂SO₄  in the chemical reaction then carbon sulphur dioxide gas will be produced instead of hydrogen gas,

11. Draw neat and clean diagram of laboratory preparation of carbon dioxide. Write the name of salt used in this process.

The name of the salt used in this process is calcium carbonate.

12.  Although the use of pesticides is considered a major concern for agriculture, write two reasons why its use continues.

Although the use of pesticides is considered a major concern of Agriculture the two reason why it is used continuously are:

(i) Pesticides help protect crops from pests and diseases and thus increases agricultural productivity.

(ii) They reduce crop losses and ensure food security for a growing population.

13. Among the animals Peacock, Crocodile, Snake, Whale and Sea-horse, which is the mammals and which is the least developed animal?

Among the animals peacock crocodile snake whale and seahorse whale is a mammal and Sea horse is least developed animal.

14. How much heat energy is required to raise the temperature 700 g water from 5℃ to 40℃ ?

Here,

Mass of water (m)=700 g=0.7 kg

Specific heat capacity of water (s)=4200 J/kg∘C

Initial temperature (t1) = 5⁰C

Final Temperature (t2) = 40⁰C

Difference in temperature (ΔT) =40^∘C−5∘C=35∘C

Heat energy required (Q) = ?

We have formula,

Q=msΔT

Putting the values in the above equation,

Q=0.7×4200×35

=102900J

Therefore,  Required heat energy = 102,900 joules

 

15. If you are applying the process shown in  the diagram to get pure silver from impure silver, then

(i) Between A and B, in which part will you put impure silver?

We will put impure silver in part A,

(ii)  What is the role of 'C' in obtaining pure silver?

Here C is silver chloride. Silver chloride (AgCl) acts as a source of silver ions (Ag⁺) in the electrolyte solution. During electrolysis.

16.  Write the structural formula of the saturated hydrocarbon having molecular mass 44 amu. Write the IUPAC name of the compound which is obtained by removing two hydrogen atoms from adjacent carbons.

The structural formula of the saturated hydrocarbon having molecular mass 44 amu is

The IUPAC name of the compound which is obtained by removing two hydrogen atoms from adjacent carbons is Prop-1-ene (Propene).

(Section 'D')

Write long answer to the following questions. (7×4=28)

17. Write any two characteristics of each of s-block and p-block elements of modern periodic table.

Two characteristics of each s-block and p-block elements of modern periodic table are:

s-block elements:

• (i) They are highly reactive metals, especially alkali (Group 1) and alkaline earth metals (Group 2).
• (ii) They have low ionization energies and readily lose electrons to form positive ions (cations).

p-block elements:

• (i) They include metals, nonmetals, and metalloids, showing a wide range of properties.
• (ii) They often form covalent bonds and include important elements like carbon, nitrogen, and oxygen.

18. Find independent and dependent variables in following events.

(i) more growth of plant in sunlight

Independent variable: Amount of sunlight

Dependent variable: Growth of plant

(ii) measuring the stretch of a catapult and the distance covered by the stone thrown by it.

Independent variable: Stretch of the catapult

Dependent variable: Distance covered by the stone

19. Draw a diagram to show the dispersion of white light as it passes through a prism. Write two causes of dispersion of light.

The diagram that shows the dispersion of white light as it passes through a prism is given below:

 

20. Report of WBC, RBC and Platelet counts of a person is shown into following table.

Blood cells)	(No. of blood cells)
W	30,00,000
X	3,000
Y	3,50,000

 

(i)                  Which of the blood cells is in normal condition?

The blood cell Y (Platelets) is in normal condition because its normal range is 1,50,000 to 4,50,000.

(ii)               Write a problem that arises due to the number of X blood cells.

X blood cell is WBC which is below the normal range. A low WBC count weakens the immunity system and makes a person prone to infection. This condition is called leukopenia.

(iii)             If the counts of cell Y decrease and reaches 1,50,000 what would be the problem in the person?

If the count of cell Y decreases and reaches to 1,50,000 then there will be difficulty in blood clotting. The person is supposed to be suffer from haemophilia.

(iv)              Name the blood cell W.

The blood cell W is RBC.

21. (i) When 240 V is passed in the primary coil of a transformer, 480 V is induced in secondary coil, if there are 300 turns in primary coil how many turns will be in secondary coil?

Solution:

Here, Primary voltage (Vp) = 240 V

Secondary Voltage (Vs) = 480 V

Number of turns in primary coil (Np) = 300

Number of turns in secondary coil (Ns) = ?

According to the formula of transformer,

Putting the values in the above formula,

Or, 

Ns = 2×300 = 600 turns

Therefore, the number of turns in secondary coil is 600 turns.

(ii) Why is the core of transformer laminated?

The core of the transformer is laminated to reduce eddy current and minimizing the energy loss.

(iii) Can transformer be used in DC circuit? Give reason.

No, a transformer cannot be used in a DC circuit. This is because  A transformer works on the principle of electromagnetic induction, which requires a changing magnetic field. DC provides constant current, so it does not produce a changing magnetic field, and hence no voltage is induced in the secondary coil.

22. Nowadays, sperms are collected from a male animal by artificial methods and fertilization is done by inserting sperms mechanically into the uterus of a female.

(i)  Write any two advantages of this technology.

Two advantages of artificial insemination (AI) are:

(a) It allows the use of high-quality sperm from superior males to improve offspring traits.
(b) It reduces the risk of transmitting diseases through natural mating.

(ii) Write two points to be considered while performing this technology?

Two points to be considered while performing this technology are:

(a) The semen should be collected, stored, and handled hygienically to avoid contamination.
(b) The female should be inseminated at the correct time of her reproductive cycle (oestrus) for successful fertilization.

23. In the given figure, mass of A and B are 6 x10²⁴ kg and 400 kg respectively, and the radius of A is 6400 km.

 

(i) Calculate the gravitational force between the objects A and and B.

Here,

Mass of A (M) = 6×10²⁴ kg

Mass of B (m) = 400 Kg

Distance between A and B = Radius of A (since the radius of B is very less, so its radius is neglected)

i.e. R = 6400 Km = 6400×1000 = 6.4×10⁶m

Gravitational Force (F) = ?

We know that,

Gravitational constant (G) = 6.67×10^-11Nm²Kg^-2

According to the formula,

Putting the values of G, M, m and R in the above equation, we get

Or, 

Or, F = 3.91×10³N

Therefore gravitational force between A and B is 3.91×10³N.

(ii) To what height the body B should be taken from the surface of the body 'A' so that the value of acceleration due to gravity becomes 6 m/s²?

Here,

Acceleration due to gravity (g) = 6m/s²

Radius (R) = 6.4×10⁶m

Height (H) = ?

We know that,

or, 6.4×10⁶+H = 8.17×10⁶

Or, H = 8.17×10⁶ -6.4×10⁶

Or, H = 1.77×10⁶ m

KARNALI PRADESH

Karnali Pradesh

SEE 2081 (2025)

Section 'A'

Multiple Choice Questions

Choose the best alternative to the following questions and write in the answer sheet. 10×1=10

1. (a) Which one of the following is a derived unit?

(i) Candela                     (ii) Ampere                     (iii) Newton                   (iv) Mole

(b)What is the reason of keeping sea-urchin in phylum Echinodermata?

(i) Due to body being divided into head, thorax and abdomen

(ii) Due to locomotion with the help of tube-feet

(iii) Due to body being flat and thin like a tape

(iv) Due to them being found in moist soil and water

(c) Which disease is caused due to the deficiency of white blood cells in blood suddenly?

(i) leukopenia               (ii) haemophilia           (iii) anemia      (iv) leukemia

(d) In the given organism, what is the relationship between caterpillar and fungi?

(i) saprotrophic                          (ii) parasitic                   (iii) predator                  (iv) symbiotic

(e) What could be the weight of a body on the Earth if its weight on the Moon is 5N ?

(i) 6 N                                              (ii) 5 N                              (iii) 30 N                         (iv) 50 N

(f) Which type of lens is thicker at middle and thinner at edges?

(i) concave lens                         (ii) convex lens             (iii) plano convex               (iv) plano concave

(g) Under what condition can a flat universe be hypothesized?

(i) when the average density is greater than the critical density

(ii) when the average density is less than the critical density

(iii) when the average density and critical density are equal

(iv) when the average density and critical density are not comparable

(h) What are the products obtained in a reaction between hydrochloric acid and sodium hydroxide?

(i) NaNO₃ + H₂         (ii) NaCl+ H₂O              (iii) NaNO₃+ H₂O              (iv) NaNO3 + O2

(i) What does carbogen indicate?

(i) Mixture of carbon dioxide and nitrogen

(ii) Mixture of carbon dioxide and hydrogen

(iii) Mixture of carbondioxide and water

(iv) Mixture of carbondioxide and oxygen

(j) Which of the following hydrocarbons group belongs to alkyne?

(А)                                             (B)

(C)                                                        (D)

(i) A and C                      (ii) A and B                      (iii) A and D                    (iv) B and C

Section 'B'

Write very short answers to the following questions. 9×1=9

2. (a) What is online reputation?

Online reputation refers to the perception or opinion that people have about an individual, brand, company, or organization based on their digital presence—including content on websites, social media, reviews, forums, and news articles.

(b) On the basis of their features, which one is less developed animal?

 

B (Shark) is less developed animal than A (whale).

(c) What is the name of blood vessel that brings pure blood to the heart?

The blood Vessel that bring pure blood to the heart is pulmonary vein.

(d) What is magnetic field?

A magnetic field is the region around a magnetic material or a moving electric charge in which the force of magnetism can be felt.

(e) Why is Big-Bang theory considered the most reliable theory among all the theories related to the origin of universe ?

The Big Bang theory is considered the most reliable because it is strongly supported by observational evidence, such as:

• Cosmic Microwave Background Radiation (CMBR)
• Redshift of galaxies, indicating that the universe is expanding
• Abundance of light elements (like hydrogen and helium) in the universe.

(f) Give an example of combination reaction.

An example of combination reaction is :

              C + O₂ à CO₂

(g) Write the molecular formula of the compound 'X' in the given chemical equation.

X + H₂SO₄ à Na₂SO₄ + H₂O

The molecular formula of compound X is NaOH.

(h) Write the molecular formula, of the acid formed when carbon dioxide gas is dissolved in water.

The molecular formula of the acid formed when carbon dioxide gas is dissolved in water is H₂CO₃ (Carbonic acid).

(i) Which element acts as a foaming agent in Reetha?

The substance or element acts as a foaming agent in Reetha is saponin.

(Section 'C')

Write short answers to the following questions. 14×2=28

3. Define fundamental unit and give one example.

A fundamental unit is a basic unit of measurement that is not derived from other units.
Example: metre (m) – unit of length.

4. Fern is not a flowering plant; cycas bears flowers but no fruit; banana bears flowers as well as fruits. However all these plants are kept in same division. Give any two reasons, why they are all kept in the same division.

. Fern, cycas, and banana are kept in the same division because:

• All three reproduce via seeds or spores and show alternation of generations.
• All are vascular plants, i.e., they have xylem and phloem.

5. Write any two differences between drone bee and worker bee.

Two differences between drone bee and worker bee:

• Drone bee is male, while worker bee is female.
• Drone bees do not collect nectar, but worker bees do.

6. Why did Mendel choose pea plant for his experiment? Give any two reasons.

Mendel chose pea plant because:

• It had easily observable contrasting traits.
• It had a short life cycle and could self- or cross-pollinate.

7 Two types of cell division are shown below.

A: Cell Division àReproductive cell à Gamete formation                Process (P)                  

      2n à            Somatic Cell à           Growth                            Process (Q)                                               

 (i) What type of cell division does A represent?

Cell division A represents meiosis cell division.

(ii) Write any one difference between these two types of cell divisions?

One difference between these two types of cell division is: haploid cells are produced as a result of meiosis Cell Division while diploid cells are produced due to the mitosis cell division.

8. Write the name of plant which is used in the treatment of burn. Write one other use of this plant.

The name of a plant which is used in the treatment of burn. The other use of aloe vera plant Is to make cosmetics and skin care products.

9. If the weight of a cricket ball in water is 2 N and the weight of the water

displaced by it is IN,

(i) What is the actual weight of the cricket ball?

Actual weight = weight in water + buoyant force (weight of displaced water) = 2 N + 1 N = 3 N
(ii) On which principle is this experiment based?

This experiment is based on the Archimedes’ principle.

10. Water pipes burst in very cold places in winter. Write any two reasons for this.

Two reasons why water pipes burst in very cold places in winter are:

• Water expands when it freezes.
• Ice forms and increases internal pressure in the pipe.

 

11. If a substance of mass 500 g needs 5980 J of heat to increase its temperature from 100 ℃ to 226 ℃, calculate its specific heat capacity.

Given:

• Mass (m) = 500 g = 0.5 kg
• Heat (Q) = 5980 J
• Temperature change (ΔT) = 226 – 100 = 126°C
• Specific heat capacity of water (s) = ?
  We have Formula:

Q = ms ΔT

Putting the values of Q, m and ΔT in the above equation, we have

5980 = 0.5 × s × 126

Or s =  = 94.92 J/Kg C

12. State two reasons why rainbow always appears semicircular, and of the same thickness from the surface of the earth.

Two reasons why a rainbow always appears semicircular and of the same thickness from the surface of the Earth:

• Light is reflected and refracted at a fixed angle (42°) inside water droplets.
• The observer can only see the part of the circle above the horizon, forming a semicircle.

13. A student inserted a burning matchstick into a gas jar and it extinguishes. Write the balanced chemical equation of a reaction that takes place when a burning magnesium ribbon is inserted into the gas jar.

Gas in jar is  CO₂

When CO2 is reacts with burning magnesium ribbon, CO₂ is reduced to Carbon. Balanced equation of this reaction is

2Mg+CO₂→2MgO+C

14. Write any two differences between mineral and ores.

Two differences between mineral and ore:

Mineral	Ore
A naturally occurring substance with metals/non-metals.	A mineral from which metal can be extracted profitably.
May not always be economically useful.	Always economically viable.

 

15. Write the name and structural formula of the alcohol having two carbons.

The name of the alcohol having two carbon atoms is ethanol and its structural formula is:

16. The use of detergent is harmful, from environmental perspectives. Give any two reasons for this.

Two environmental harms of detergents:

• They cause water pollution and eutrophication in rivers and lakes.
• They are non-biodegradable, harming aquatic life.

 

Section 'D'

Write long answer to the following questions. (7×4=28)

17. Write any two positive and any two negative effects of digital technology in daily life.

Two positive and two negative effects of digital technology in daily life

Positive Effects:

1. Digital technology enables instant communication via messaging, video calls, and emails.
2. It provides quick access to educational resources, news, and information from around the world.

Negative Effects:

1. Overuse of digital devices can lead to addiction, reducing productivity and affecting mental health.
2. Increased use of digital platforms can lead to personal data being exposed or misused.

18. Draw a chart to show both phenotype and genotype of offsprings produced from dogs of black (BB) and white (bb) colour in the 1^st and 2^nd filial generation according to Mendel's experiment. Write the ratio of phenotype and genotype of second filial generation.

Mendel’s Experiment: Dog Color Inheritance Chart

Given:

• Black Dog Genotype = BB (Homozygous dominant)
• White Dog Genotype = bb (Homozygous recessive)

F₁ Generation (1st Filial Generation):

Cross: BB × bb

Parent Genotypes	Gametes	Offspring Genotype	Offspring Phenotype
BB × bb	B, b	100% Bb	100% Black

F₂ Generation (2nd Filial Generation):

Cross: Bb × Bb

Gametes: B, b × B, b
Male Female	B	b
B	BB	Bb
b	Bb	bb

• Genotype ratio: 1 BB : 2 Bb : 1 bb
• Phenotype ratio: 3 Black : 1 White

 

19. Following results were obtained when the blood samples of four people were tested.

A - RBC count is low                             B - WBC count is high

C - Platelets count is low                  D - amount of sugar is high

(i) The person with which blood sample bleeds more during injuries.

The person C with platelets count low bleeds more during injuries.

(ii) The person with which blood sample becomes tired even after a short walk?

The person A with RBC count low becomes tired even after a short walk.

(iii) The person with which blood sample needs to take antibiotic?

The person B with high WBC count needs to take antibiotics.

(iv) The person with which blood sample could have problems in kidney.

The person D with high sugar level could have problem in kidney.

20. State Newton's Universal law of gravitation and prove that  with the help of appropriate diagram.

According to the Newton’s law of gravitation, the force of gravitation between two bodies is directly proportional to the Product of their masses and inversely proportional to the square of the stance between their centers."

Consider two bodies having masses m1 and m2 are separated by the distance and the gravitational force between them is 'F'.

According to Newton's law of gravitation,

F α m1× m2 ............(i) (When d is constant)

F α................(ii) (When m1 and m2 are constant)

from the equation (i) and (ii) we have

Fα-

Or,  (Where 'G' is gravitational constant' whose value is 6.67x 10^-11Nm²/kg²)

 

21. Mention the types of these two lenses. Out of these two lenses which one forms a virtual and magnified image when an object is kept 15 cm away from the lens? Draw and appropriate ray diagram of this.

(Lenses)	(Focal Length)
A	+20 cm
B	-25 cm

The types of Lenses are: A is Convex Lens and B is Concave Lens.

 

22. Study the given figure.

 (i)

i) Name the type of transformers X and Y.)

(iii) Write any two problems of transmitting electricity the way shown in figure A.

23. (i) State modern periodic law.

(ii) If Element : A = 1s², 2s²,2p⁶, 3p² and Element B= 1s², 2s²,2p⁴

(iii) In which group of periodic table does element B lie?

(b) Write the balanced chemical equation obtained in the reaction between A and B.