JKBOSE Class 10th Science Model Paper 2023-24 Solved

 The below Questions have been added to the respective units wherever necessary. The answers have been prepared in concise and simple language to suit my Govt school children

 

JKBOSE Class 10th Model Paper 2023-24 Solved, Mufawad

Section A

 

1.      The radius of Curvature of a spherical mirror is 20cm. What is its focal length?

a.      12 cm   b. 10 cm   c. – 10 cm   d. 2cm

Ans: 10 cm

 

2.      Power of Concave lens of focal length 200 cm.

a) 0.8 D    b) 1.5 D    c) 0.5 D     d) 5 D

Ans: 0.5 D   (Power of Concave lens is Negative)

 

3.      The change in focal length of eye lens is caused by the action of the:

a) Pupil    b) Retina   c) Ciliary muscles   d) Iris

Ans: c) Ciliary muscles  

 

4.      How much work is done in moving a charge of 2C across two points having potential difference 12V?

a) 24 J    b) 26 J   c) 12 J   d) 2.4 J

Ans: a) 24 J   

 

5.      The device used for producing electric current is called

a) generator   b) Ammeter  c) galvanometer    d) motor

Ans: a) generator  

6.      A solution turns red litmus blue, its PH likely to be:

a) 1   b) 5   c) 4   d) 10

Ans: d) 10

 

7.      In order to balance the following chemical equation, the value of Cofficients x and y resp. are

                         xpb( NO3)2    Heat  >    2Pbo + yNo2 + O2

a) 2, 4   b) 2, 2   c) 2, 3   d) 4, 2

Ans: a) 2, 4  

                         2Pb( NO3)2    Heat  >    2Pbo + 4NO2 + O2

8.      Ethane with molecular formula C2H6 has:

a) 6 Covalent bonds   b) 8 Covalent bonds    c) 7 Covalent bonds   d) 9 Covalent bonds

Ans: c) 7 Covalent bonds  

9.      Food cans are Coated with tin and not with zinc because

a) Zinc is more reactive than tin      b) Zinc is less reactive than tin

c)Zinc is costlier than tin                  d) zinc has higher melting point than tin

Ans:  a) Zinc is more reactive than tin

 

10.   Melting point of Acetic acid is:

a) 290 K  b) 209 K   c) 391 K   d) 211 K

Ans: a) 290 K  or 17^oC

11.   The kidney in human beings are part of which system:

a) Nutrition  b) Respiration   c) Excretion  d) transporation

Ans: c) Excretion 

 

12.   The brain is responsible for:

a) Thinking  b) Balancing body   c) Regulating the heart beat  d) All of the above

Ans:  d) All of the above

13.   The Anther contains:

a) Sepal   b) Pistil   c) Ovules    d) pollen grains

Ans: d) pollen grains

 

14.   In evolutionary terms we have more in common with:

a) a Chinese school boy   b) a spider   c) a chimpanzee  d) a bacterium

Ans: a) a Chinese school boy  

15.    ……………………. living has always been part of India's tradition and culture.

a) Sustainable    b) Sad   c) Happy  d) Economic

Ans: a) Sustainable   

 

Note: For QNo's 16 to 18, two statements (Assertion 'A' and Reason 'R') are given. Select the Correct answer to these questions from the Codes (a), (b),(c) and (d) as given below:

Code(a):A and R are true and R is correct explanation of A

Code(b): Both A and Rare true and R is not correct explanation of A

Code(c): A is true but R is false

Code(d): A is false but R is true

 

16.   Assertion (A): Magnetic field lines don't intersect each other

Reason (R): Magnetic field lines are imaginary lines, the tangents to which any point gives the direction of the field at that point.

Ans: A and R are true and R is correct explanation of A

 

17.   Assertion(A): Metalloids are classified as semi-metals

Reason (R): Metalloids are intermediate in properties then exhibit properties of both metals and non- metals.

Ans: A and R are true and R is correct explanation of A

 

18.   Assertion(A): Anaerobic respiration, one of the end product is alcohol.

Reason (R): There is an incomplete breakdown of glucose.

Ans: Both A and Rare true and R is not correct explanation of A

19A. The focal length of a plane mirror is:

a) 0 b) infinite c) 25 cm d) -25 cm

Ans: b) Infinite



19B. Electrical resistivity of a given metallic wire depends upon:

a) its length   b) its thickness   c) its shape   d) nature of material

Ans: d) Nature of material


19C. The device used to measure electric current is called

a) Generator   b) Ammeter   c) Galvanometer   d) Motor

Ans: b) Ammeter


19D. A student performs an experiment to form aluminium chloride from aluminium and chlorine. Which of the following option gives the chemical equation of the reaction.

a) Al + Cl2 -> AlCI2

b) 2Al +3Cl, > 2AICl,

c) 2Al + CI2 -> 2AICI

d) 3Al +3Cl3 -> 3AICI3

Ans: d) 3Al +3Cl3 -> 3AICI3


19E. Which of the following reaction is used in black and white photography.
a) Combination reaction   d) Oxidation reaction
b) Decomposition reaction   c) Displacement reaction


Ans: b) Decomposition reaction


19F. Which statement is not correct regarding the food chain.
a) Every component of food chain forms trophic level
b) Interrelation between different food chains is food web
c) All chains formed by nutritional relations are used to understand energy flow
d) Energy level increases from lower trophic level to higher trophic level.


Ans: d) Energy level increases from lower trophic level to higher trophic level.

SECTION -B

 

Note: - There will be 10 Questions in this Section. Q.No's from 19 to 28 ( Each of 2 Marks)

 

19.   Why planets don't twinkle?

Ans: Planets don’t twinkle because they are very close to earth and appear larger than the stars. Thus earth’s atmosphere doesn’t cause much refraction in the light from planets.

 

20.    Discuss four properties of ionic compounds.

Ans: The four properties of Ionic compounds are:

i.                 They have high melting point

ii.                They have high boiling point

iii.               They conduct electricity

iv.               They are brittle

 

21.   Why do acids don't show acidic behaviour in the absence of water?

Ans: The acids don’t show acidic behaviour in the absence of water, because they do not dissociate to produce H+ ions in the absence of water.

22.    An electric motor takes 5A from a 220V line. Determine the power of the motor and energy consumed in 2 hours?

Ans: Given:

I = 5 A

V = 220 V

T = 2 h i.e. 7200 s.

We Know:

The power of the electric motor P = V × I

P= 220 x 5

P = 1100 Watts.

Also,

The energy consumed by the electric motor = Power x Time

P = 1100 x 7200

P = 79,20,000 Joules

23.   Define Ohm's Law and draw the Circuit diagram.

Ans: Ohm's law states that the electric current flowing through a conductor is directly proportional to the potential difference across its two ends.

24.   Show would you able to check if the water is hard by using detergent?

Ans: Detergents cannot be used to check the hardness of the water, as they lather easily in both soft and hard water. However, the hardness of water can be detected using soaps, as soaps don't lather easily in hard water.

25.    What Criteria do we use to decide whether something is alive?

Ans: The criteria we use to decide whether something is living is that if it show Growth, Respiration, Nutrition, Excretion and Reproduction.

26.   Why is DNA Copying an essential part of the process of reproduction?

Ans: DNA copying mantains body design and perfection in different generations of a species.
Error in DNA copying can lead to abnormalities in the population.

27.   How do Mendel’s experiment show that traits may be dominant or recessive?

Ans: When Mendel cross bred two pea plants of opposite traits such as tall and short pea plant, All the plants of F1 generation were tall and hence dominant. In this way Mendel showed traits may be dominant or recessive.

28.   How does our body respond when adrenaline is secreted into blood?

Ans: When Adrenaline is secreted into blood, It increases heart rate and blood pressure. It also dilates our blood vessels.

28A. Give the formula of:

a) Plaster of Paris

b) Baking soda

Ans:

a) Plaster of Paris: The chemical formula of Plaster of Paris is CaSO4.1/2H2O

b) Baking Soda: The chemical formula of Baking Soda is Na2CO3.10H2O

 

SECTION-C

 

Note :- There will be 9 questions [ Short Answer With internal choice (Each of 3 Marks) ]

Q.No's 29 to 37

 

29.   Write Sign Convention for spherical mirrors

Ans: The sign conventions for Spherical mirrors are as following:

i. Object is always taken on the left side of mirror.

ii. All the distance taken on the left side of mirror are taken as negative

iii. All the distance taken on the right side of mirror are taken as positive

iv. All the heights that are erect are taken as positive

v. All the heights that are inverted are taken as negative

30.   A Concave lens has focal length of 15cm. At which distance should the object from the lens be placed so that it forms an image at 10cm from the lens? Also find the magnification produced by the lens.

Ans: Given:

F = - 15

V = - 10

U = ?

M = ?

 

We know,

1/V – 1/U = 1/F

1/-10 – 1/U  = 1/-15

1/U = 1/-10 + 1/15

1/U =  - 3 + 2/30

1/U = - 1/30

U = - 30

Thus, object distance is 30 cm.

Now, Magnification, M =  V/U

M = - 10/ -30

M = 10/30

M = 0.33

Thus, Image is diminished and erect.

 

31.    Explain Myopia with its occurrence and Correction

Ans: Myopia means short sightedness. A person sees nearby objects clearly but can't see distant objects.
In myopia, the rays of light meet Infront of Retina.
It is treated by Concave lens.

32.   Explain Hypermetropia with Occurrence and Correction.

Ans: Hypermetropia means long sightedness. A person sees far off objects clearly but cant see nearby objects.
In hypermetropia, the days of light meet behind Retina.
It is treated by convex lens.

33.   100J of heat is produced each second in a 4 Ω resistance. Find the potential difference across the Resistor.

Ans:  Given:

H = 100 J

R = 4 Ω

T = 1 S

We Know;

H = 1² R T

100 = I² x 4 x 1

I = √25

I = 5A

 

Now,

V = I R

V = 5 x 4

V = 20 V

 

34.   Why is the series arrangement not used for domestic circuits.

Ans:  The equivalent resistance in series is large. It can produce heat and fire.
If one resistance breaks, the whole circuit will not work.

35.   How would you distinguish experimentally between an alcohol and a carboxylic acid?

Ans: Carboxylic acid is an acid whereas Alcohol is a base. Carboxylic acid will turn blue litmus red whereas alcohol will have no effect on litmus paper.

Carboxylic acid reacts with Sodium Bicarbonate where as alcohol will not react with sodium bicarbonate.

 

36.   Explain oxidizing agents with examples.

Ans: Oxidizing agents are the chemicals which give oxygen in an oxidation reaction.

E.g Potassium Permagnate (KMnO4).

Potassium Dichromate  (K2Cr2O7)

 

37.    Why pure gold is not suitable for making jewellery?

Ans:  Pure gold is very soft and can't be used for making ornaments. so, some amount of other metal such as copper or silver is added to make gold a bit harder.

38.   Define the following terms:

a.      Mineral    b. Ore    c. gangue

Ans: a. Mineral: The compounds of elements along with impurities occurring in earth’s crust are called minerals.
b. Ore: An Ore is mineral from which the element is extracted.
c. Gangue: The impurities present in the ore is called gangue.

 

39.   Why magnesium ribbon is cleaned before heating?

Ans: Magnesium is very reactive and should be cleaned before burning to remove the Magnesium oxide layer from the ribbon which  slows down the burning of magnesium ribbon.

40.   Balance the following reaction

a.       Zn + CusO4 ----à ZnSO4 + Cu

b.      Na + O2 ----à Na2O

c.      HNO3+ Ca(OH)2 ---à Ca(NO3)2 + H20

Ans:

a.       Zn + CusO4 ----à ZnSO4 + Cu

b.      4Na + 02 ----à 2Na20

c.      2 HNO3+ Ca(OH)2 ---à Ca(NO3)2 + 2 H20

 

41.   What are the differences between the transport of materials in Xylem and phloem?

Ans:

Xylem	Phloem
Xylem transports soluble minerals and water molecules.	Phloem transports food and other nutrients like sugar and amino acids.
Water is absorbed by the roots and is transported to the aerial parts of the plant like the stem and leaves.	Food is formed in the leaves from where it is transported to the storage organs and the growing parts of the plants.
Xylem tissues are composed mainly of dead cells.	Phloem tissues are mainly composed of living cells.
Transportation in the xylem is unidirectional from roots to leaves.	Phloem transportation is bidirectional from leaves to various plant parts.
Xylem consists of tracheids, vessels, parenchyma, and fibers.	Phloem consists of sieve tubes, companion cells, parenchyma, fibers.

 

42.   Describe Double Circulation of blood in human beings. Why is it necessary?

Ans: Humans undergo double circulation. It was first discovered by William Harvey.
The blood passes through the heart twice in following steps:

Step 1: The deoxygenated blood from body enter right auricle via superior and inferior vena cava.
Step 2: From right Auricle, blood enters into right ventricle via Tricuspid valve.
Step 3: From right ventricle, the deoxygenated blood flows into lungs via pulmonary artery. The blood is oxygenated in lungs.
Step 4: The oxygenated blood enters left auricle via pulmonary vein.
Step 5: From left auricle, the blood enters left ventricle via bicuspid valve.
Step6: From left ventricle, the oxygenated blood flows back to body via aorta. 

 

Importance of Double Circulation: Double circulation is important because it separates oxygenated and deoxygenated blood and increases oxygen transport efficiency.

43.    How does binary fission differ from multiple fission?

Ans:

Binary Fission	Multiple Fission
The Parent cell divides into two daughter cells	The Parent cell divides into many daughter cells
Cytoplasm divides after every nuclear division	Cytoplasm doesn’t divide after every nuclear division
In some organism occurs in favourable conditions	Occurs in unfavourable conditions

 

44.   Why is Vegetative propagation practised for growing some types of plants?

Ans: Vegetative propagation is a type of reproduction in which new plants grow from vegetative parts of a plant. It is practised for growing some types of plants because:

A. It helps us to grow seedless plants

B. Vegetative propagation is a cheaper, easier and more rapid method.

C. It produces identical individuals as similar to the parent.

 

45.   What will happen if we kill all the organisms in one tropic level.

Ans: In a food chain, the energy transfer takes place from one trophic level to another.
If all organisms in one trophic level are killed, the whole food chain will collapse.

46.   What is Ozone and how does it affect any ecosystem?

Ans: Ozone is a gas made up of three oxygen atoms (O3).

Ozone is vital for all ecosystems on Earth because it protects the environment from the harmful effects of UV radiation. These rays can cause skin cancer, cataracts, and other damages. 

46A. What are electric field lines. Give their properties?

Ans: Electric field lines are lines or curves that show electric field around the charges.

They are similar properties as magnetic field lines.

Properties:

Electric field lines start from the positive charge (+) and end at Negative charge (-)

They never intersect each other

They do not pass through a conductor

 

46B. State Fleming's Left-Hand rule with the help of diagram.

Ans: : Flemings left hand rule states that if we stretch the thumb, fore finger and middle finger of our left hand in such a way that they are mutually perpendicular to each other like X, Y and Z axis of a graph.

The forefinger represents points towards magnetic field, the middle finger points towards direction of current, then thumb points towards direction of motion of the conductor.

 

 

46C. Distinguish between saturated and unsaturated hydrocarbons.

Ans: 

Saturated Hydrocarbons	Unsaturated Hydrocarbons
They have single covalent bond	They have double or triple covalent bond
The general formula is CnH2n+2	The general formula is CnH2n or CnH2n-2
They are less reactive	They are more reactive
They include Alkanes	They include Alkenes and Alkynes
They burn with clean flame	They burn with sooty flame

 

47D. Define corrosion of metals and give its prevention methods.

Ans: Corrosion is a natural process that occurs when a metal deteriorates due to chemical reactions with air and moisture.

Prevention: The Corrosion can be prevented by following methods:

Painting,

Oiling,

Greasing,

Galvanizing,

Chrome Plating,

Anodizing

Alloying

 

47E. Differentiate between autotrophic and heterotrophic nutrition.

Ans:

Autotrophic Nutrition	Heterotrophic Nutrition
In this type of Nutrition, organisms prepare their own food	In this type of nutrition, Organisms depend on others for food
It is of two types: Photoautotrophic and Chemoautotrophic	It is of many types: Holozoic, Saprotrophic, Parasitic
It includes green plants, blue green algae, euglena, some bacteria	It includes animals, non-green plants, fungi, some bacteria

 

 

SECTION-D

Note :- There will be 3 Long Answer Type Questions with internal choice [ Each of 5 Marks] [Q. NO's 38 to 40]

 

47.   Define Power of Lens and give its S.l unit. Also describe magnification produced by lens.

Ans:  The Power of lens (P) is the ability of lens to converge or diverge the rays of light.
Lesser the focal length of lens, the more it converges or diverges the light. i.e,
                          P = 1/F
Its SI unit is dioptre, 1 dioptre means the power of lens whose focal length is 1 metres.
Power of Convex lens is Positive and power of Concave lens is negative.

 

Magnification of Lens: The ratio of the height of an image (H’ ) to the height of an object ( H) is defined as the magnification of a lens.

M = H’/H  = V/U

48.    Explain Snell's Law.

Ans: Snell’s law is defined as “The ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant, for the light of a given colour and for the given pair of media”. 

Snell’s law formula is expressed as:

Sin <i/ Sin <r = Constant = Refractive Index

 

49.   Why Sky appears dark instead of blue to an astronaut?

Ans: Sky appears blue to us due to scattering of light. The sky appears dark to astronauts because there is no atmosphere in outer space to scatter sunlight. 

50.   How is Voltmeter Connected in the Circuit to measure the potential difference between two points?

Ans: The Voltmeter is connected in Parallel to measure the potential difference between two points across a conductor.

51.   What is an Esterification Reaction? Describe an activity to show esterification.

Ans:  Esterification is a chemical reaction that occurs when an alcohol and a carboxylic acid react in the presence of an acid catalyst. The reaction produces a compound with a sweet smell called an esters.

Activity to show Esterification:

i. Add 1 ml of pure ethanol to a test tube

ii. Add 1 ml of ethanoic acid to the ethanol

iii. Add 2 to 3 drops of concentrated sulfuric acid to the mixture

iv. It will produce Esters

Example:

 CH3COOH + C2H5OH --H2SO4-->   CH3COOC2H5  + H2O

52.   Write the uses of Baking Soda

Ans: Baking soda is NaHCO3.
Its uses are:
1. It is used to make baking powder.
2. It is used as antacid.

53.   Draw election dot structure for Ethanoic acid.

 Ans: 

54.   Why is respiration Considered an exothermic reaction.

Ans: Respiration is considered an exothermic reaction because it releases energy. This process involves the breakdown of glucose and other organic molecules to produce energy in the form of ATP (adenosine triphosphate).

55.   How and where does fat digested

Ans: Fat digestion occurs in the small intestine. The liver produces bile juice, which contains bile acids that break down large fat molecules into smaller droplets. 

This process is called emulsification. The smaller fat droplets are then more easily digested by enzymes in the small intestine. 

 

56.   Why Pituitary gland is called Master gland?

Ans: The pituitary gland is called the "master gland" because it produces hormones that regulate many bodily functions.

57.   Name two biodegradable substances.

Ans: Biodegradable substances are organic waste matters that can be broken down into compost or simple organic molecules by biological means. These substances can decompose due to the action of microorganisms.

Examples includes Fruits, vegetables, human waste, etc.

 

58.   What is photosynthesis and write its reaction?

Ans: Photosynthesis is the process by which plants convert light energy into chemical energy. The equation for photosynthesis is: 

6CO2 + 6H2O + sunlight → C6H12O6 + 6O2 

This means that six carbon dioxide molecules and six water molecules are converted into one glucose molecule and six oxygen molecules. 

 

59.   Define Reflex arc.

Ans: Reflex arc is a pathway through which reflex action occurs. The Components of the reflex arc includes Sensory neuron , Motor Neuron, Relay neuron and Effector muscles.

60.    Name two non-biodegradable substances

Ans: Non-Biodegradable substances are those waste matters that cannot be broken down into compost or simple organic molecules by biological means.

Examples includes Plastics, Polythene, Pesticides, Metals.

61. What are conclusions of Oersted's experiment.

Ans: Hans Christian Oersted performed an experiment in 1820 which helped us to understand that the electricity and magnetism are related.

Oersted concluded that the current carrying conductor produces a magnetic field around it.



62. Draw a diagram to represent uniform magnetic field.

Ans:

63.  State direction of magnetic field inside a bar magnet.

Ans: The direction of the magnetic field inside a bar magnet is from the south pole to the north pole.



64. What is allotropy? Give names of allotropes of carbon.

Ans: When an element exists in different physical forms but having similar chemical properties. The phenomenon is called allotropy and the various forms are called allptropic forms.

Carbon exists in various allotropic forms such as Diamond, Graphite, Fullerene.


A. Diamond: In a diamond One carbon is attached to 4 other carbon atoms to form rigid 3D structure.
It is hardest and bad conductor of electricity.


B. Graphite: In graphite, one carbon is attached to 3 other carbon atoms to form hexagonal array.
It is soft and good conductor of electricity.


C. Fullerene: It consists to 60 carbon atoms in form of dome.



65. Why covalent compounds have low melting and boiling points?

Ans: The covalent compounds have low melting and boiling points because of the weak intermolecular bonds (Covalent bonds) present between its atoms.



66. Which hormone regulates blood sugar level in humans?

Ans: Insulin is the hormone which regulates the blood sugar level in humans.