Note: The below solutions have been prepared in simple and concise language to suit my Govt School children plus the questions have also been added to the Notes of respective units wherever necessary!
 |
| JKBOSE Class 10th Annual Regular 2023-24 Science Solved Paper |
Section A:
X Series:
a. Both Concave b. Both Convex
c. The mirror is concave and the lens is convex
d. The mirror is convex and the lens is concave
Ans: c. The mirror is concave and the lens is convex
Q. Which of the following statements is correct?
a. A person with myopia can see distant objects clearly
b. A person with hypermetropia can see nearby objects clearly
c. A person with myopia can see nearby objects clearly
d. A person with hypermetropia cannot see distant objects clearly
Ans: c. A person with myopia can see nearby objects clearly
Q. A person cannot see distant objects kept beyond 2 m. This defect can be corrected by using a lens of power:
a. +0.5D b. -0.5D c. +0.2D d. -0.2D
Ans: b. -0.5D
Hint: The person is suffering from Myopia and hence needs a concave lens of power -0.5 D to correct the problem.
Q. The energy given to each coulomb of charge passing through a 6V battery is :
a. 12J b. 6J c. 3J d. 18J
Ans: b. 6J
Q. Which among the following is used to find the direction of magnetic field lines around a current carrying straight conductor ?
a. Amperes swimming rule b. Flemings right hand rule
c. Maxwells right hand thumb rule d. Flemings left hand rule
Ans: c. Maxwells right hand thumb rule
Q. Three solutions A, B and C when tested with universal indicator showed pH as 5, 1 and 13 respectively. Based on the observation, Choose the correct statement from the following:
a. A is strong acid and B is weak acid b. A is weak acid, C is weak base
c. Both A and B are strong acids d. B is strong acid, C is strong base
Ans: d. B is strong acid, C is strong base
Q. CuO (s) + H2 (g) -> Cu (s) + H2O (l), In this reaction:
a. Cu is an oxidising agent b. H20 is reducing agent
c. CuO is oxidizing agent d. Both CuO and H2 are oxidizing agent
Ans: c. CuO is oxidizing agent
Q. Which among the following represents the functional group of aldehydes
a. -COOH b. CHO c. -C=O d. C=C
Ans: c. -C=O
Q. An element reacts with oxygen to give a compound with a high melting point. The compound is also soluble in water. The element is likely to be:
a. Calcium b. Carbon d. Silicon d. Iron
Ans: a. Calcium
Hint: Calcium reacts with oxygen to form Calcium oxide (Quick Lime). It has high melting point and is soluble in water.
Q. Where should an object be placed Infront of a convex lens to get a real image of the size of the object?
Ans: The object should be placed at the principal focus (2F1) of the convex lens
Q. Which one of the following properties is not generally exhibited by ionic compounds?
a. Solubility in water b. Electric conductivity in Solid state
c. High M.P and B.P d. Electric conductivity in Molten state
Ans: b. Electric conductivity in Solid state
Q. Growing foetus derives nutrition from mother’s blood through:
a. Uterus b. Fallopian tube c. Placenta d. Cervix
Ans: c. Placenta
Q. Characters that are transmitted from parents to offsprings during the sexual reproduction show:
a. Only similarities with parents b. Only variations with parents
c. Both similarities and variations d. Neither similarities nor variations
Ans: c. Both similarities and variations
Q. In an ecosystem, the 10% of energy available for transfer from one trophic level to the next is in the form of:
a. Heat energy b. Chemical energy c. Light energy d. Mechanical energy
Ans: b. Chemical energy
Q. Which is the correct sequence of the components of a reflex arc?
a. Receptors > Muscles > Sensory neurons > Motor Neurons > Spinal Cord
b. Receptors > Motor neuron > Spinal cord > Sensory neuron > Muscles
c. Receptors > Spinal cord > Sensory neuron > Motor Neuron > Muscles
d. Receptors > Sensory neuron > Spinal cord > Motor neuron > Muscle
Ans: d. Receptors > Sensory neuron > Spinal cord > Motor neuron > Muscle
Q. Assertion: When a current carrying conductor is placed in a magnetic field, It experiences a force
Reason: The force acting on a current carrying conductor is only due to the external magnetic field.
A. Both A and R are true and R is the correct explanation of A
B. Both A and R are true and R is not the correct explanation of A
C. A is True, R is False
D. A is False, R is True
Ans: C. A is True, R is False
Hint: The force acting on the conductor is due to the interaction of external magnetic field and the magnetic field produced due to the current flowing in the conductor
Q. Assertion: In human males, testes are extra abdominal and lie in scrotal sac
Reason: Scrotum keeps temperature lower by 2C for normal spermatogenesis
A. Both A and R are true and R is the correct explanation of A
B. Both A and R are true and R is not the correct explanation of A
C. A is True, R is False
D. A is False, R is True
Ans: A. Both A and R are true and R is the correct explanation of A
Q. Assertion: Food web is a network of food chains which are interconnected at various trophic level
Reason: In a food web, one organism may occupy more than one position
A. Both A and R are true and R is the correct explanation of A
B. Both A and R are true and R is not the correct explanation of A
C. A is True, R is False
D. A is False, R is True
Ans: B. Both A and R are true and R is not the correct explanation of A
Y Series:
a. Concave lens of focal length 50 cm b. Concave lens of focal length 50 cm
c. Convex lens of focal length 5 cm d. A concave lens of focal length 5 cm
Ans: c. Convex lens of focal length 5 cm
Q. Which of the following statements is correct regarding the propagation of light of different colours of white light in air?
A. Red light moves fastest
b. Blue light moves faster than green light
c. Yellow light moves with the mean speed as that of the red and the violet light
d. All the colours of the white light move with the same speed
Ans: d. All the colours of the white light move with the same speed
Hint: All colours move at the same speed in the vacuum and air but in much denser medium, different colours move at different speeds.
Q. The focal length of a concave lens is 100 cm. Calculate its power in Dioptres:
a. 1 D b. 0.5 D c. 2 D d. 0.2 D
Ans: a. 1 D
Q. Three resistors having resistances of 2 ohm, 4 ohm and 8 ohm are connected in Parallel. Their equivalent resistance will be:
a. 10 ohm b. 14 ohm c. 8/7 ohm d. Between 2 ohm and 8 ohm
Ans: c. 8/7 ohm
Q. To find out the direction of deflection of the compass needle due to magnetic field of a current carrying conductor, we use:
a. Amperes swimming rule b. Flemings right hand rule
c. Maxwells Rule d. Flemings left hand rule
Ans: a. Amperes swimming rule
Q. Which of the following phenomena occur, when a small amount of acid is added to water,
i. Ionisation ii. Neutralization iii. Dilution iv. Both A and C
Ans: iv. Both A and C (Both Ionization and Dilution)
Q. 4 Na(s) + O2 (g) -> 2 Na2O (s), In this reaction,
a. Sodium gets reduced b. Sodium oxide gets reduced
c. Sodium oxide gets oxidized d. Sodium gets oxidized
Ans: d. Sodium gets oxidized
Q. Which of the following has 10 covalent bonds
a. Ethane b. Propane c. Butane d. Pentane
Ans: b. Propane
Q. Which of the following pairs will give displacement reaction?
a. NaCl solution and copper metal b. MgCl2 solution and aluminium metal
c. FeSO4 solution and Silver metal d. AgNO3 solution and Copper metal
Ans: d. AgNO3 solution and Copper metal
Q. The image formed by a concave mirror is observed to be virtual, erect and magnified. Where should be the position of the object?
Ans: The object shall be placed between the Pole and the Focus of the concave mirror.
Q. Aluminium is used for making cooking utensils. Which of the following properties of aluminium are responsible for the same?
a. Good thermal conductivity b. Good electrical conductivity
c. Ductility d. High melting point
Ans: Good thermal conductivity and High Melting point
Q. Which of the following is the correct sequence regarding sexual reproduction in flowering plant?
a. Pollination, Fertilization, Seedling, Embryo
b. Seedling, Embryo, Fertilization, Pollination
c. Pollination, Fertilization, Embryo, Seedling
d. Embryo, Seedling, Pollination, Fertilization
Ans: c. Pollination, Fertilization, Embryo, Seedling
Q. After fertilization, which of the following parts develops into seed?
a. Ovary b. Ovule c. Pollen grain d. Stigma
Ans: b. Ovule
Q. In natural ecosystem, decomposers include:
a. All microscopic organisms b. Bacteria and Fungi c. Only Bacteria d. Only Fungi
Ans: b. Bacteria and Fungi
Q. Involuntary actions in a body are controlled by:
a. Medulla in forebrain b. Medulla in Midbrain
c. Medulla in Hindbrain d. Medulla in Spinal cord
Ans: c. Medulla in Hindbrain
Q. Assertion: When the direction of current in a current carrying straight conductor is upwards, the direction of magnetic field lines is clockwise
Reason: To find the direction of magnetic field lines, we use maxwells right hand thumb rule
A. Both A and R are true and R is the correct explanation of A
B. Both A and R are true and R is not the correct explanation of A
C. A is True, R is False
D. A is False, R is True
Ans: D. A is False, R is True
Q. Assertion: Vagina acts as copulation canal and fertilization canal
Reason: Both insemination and fusion of gametes occur in vagina
A. Both A and R are true and R is the correct explanation of A
B. Both A and R are true and R is not the correct explanation of A
C. A is True, R is False
D. A is False, R is True
Ans: C. A is True, R is False
Q. Assertion: Decomposers are micro consumers
Reason: They bring mineralization of decomposed matter
A. Both A and R are true and R is the correct explanation of A
B. Both A and R are true and R is not the correct explanation of A
C. A is True, R is False
D. A is False, R is True
Ans: A. Both A and R are true and R is the correct explanation of A
Z Series:
a. Plane b. Concave c. Convex d. Either Plane or Convex
Ans: d. Either Plane or Convex
Q. The danger signals installed at the top of building are red in colour. These can be easily seen from a distance because among all the colours, the red light:
a. Is scattered the most by the smoke or fog b. Is scattered the least by the fog
c. Is absorbed the most by the fog d. Moves fastest in the air
Ans: b. Is scattered the least by the fog
Q. The power of concave lens is 0.5 D. Its focal length will be:
a. 100 cm b. 200 cm c. 150 cm d. 250 cm
Ans: b. 200 cm
Q. A wire of resistance 1 ohm is divided into two halves and both halves are connected in parallel. The new resistance will be:
a. 1 ohm b. 2 ohm c. 0.5 ohm d. 0.25 ohm
Ans: d. 0.25 ohm
Q. Magnitude of a magnetic field around a current carrying conductor at any point is:
a. Directly proportional to the intensity of electric current
b. Inversely proportional to the distance from the conductor
c. Directly proportional to the distance from the conductor
d. Both A and B
Ans: d. Both A and B
Q. Which of the following statements are correct about an aqueous solution of an acid and of a base?
a. Higher the pH, Stronger the acid b. Higher the pH, weaker the acid
c. Lower the pH, stronger the base d. Lower the pH, Weaker the base
e. Both B and C
Ans: Both B and C
Q. Fe2O3 + 2 Al -> Al2O3 + 2Fe, The reaction is an example of:
a. Combination reaction b. Displacement Reaction
c. Double Displacement reaction d. Decomposition reaction
Ans: b. Displacement Reaction
Q. Butanone is a four carbon compound with the functional group:
a. -COOH b. -CHO c. -C=O d. -C-Br
Ans: b. -CHO
Q. Which among the following is the least reactive metal:
a. Sodium b. Zinc c. Mercury d. Aluminium
Ans: c. Mercury
Q. When the object is placed beyond centre of curvature of a concave mirror, the image formed will be:
a. Erect and Dim b. Erect and Magnified c. Inverted and Dim d. Inverted and Magnified
Ans: c. Inverted and Dim
Q. Which of the following oxides of iron would be obtained on prolonged reaction with steam?
a. FeO b. Fe2O3 and Fe3O4 c. Fe3O4 d. Fe2O3
Ans: c. Fe3O4
Q. The process where the unfertilized egg is released out of the body with blood is known as:
a. Mensuration b. Fertilization c. Germination d. Pollination
Ans: a. Mensuration
Q. The testes are located outside the abdominal cavity in scrotum because:
a. Sperm formation requires more space b. Sperm formation requires a lower temperature
c. Sperm formation requires a higher temperature d. Both A and C
Ans: b. Sperm formation requires a lower temperature
Q. The decomposers in an ecosystem:
a. Convert inorganic material to simpler forms b. Convert organic material to inorganic forms
c. Convert inorganic materials into inorganic compounds d. Do not break organic compounds
Ans: b. Convert organic material to inorganic forms
Q. Which part of the brain regulates the body temperature?
a. Hypothalamus b. Thalami c. Pituitary c. Medulla oblongata
Ans: a. Hypothalamus
Q. Assertion: When a compass needle is moved away from a current carrying straight conductor, the deflection of the needle decreases
Reason: The strength of magnetic field decreases on moving away from the conductor
A. Both A and R are true and R is the correct explanation of A
B. Both A and R are true and R is not the correct explanation of A
C. A is True, R is False
D. A is False, R is True
Ans: A. Both A and R are true and R is the correct explanation of A
Q. Assertion: At puberty human male develops secondary sexual characters
Reason: There is decreased secretion of testosterone at puberty
A. Both A and R are true and R is the correct explanation of A
B. Both A and R are true and R is not the correct explanation of A
C. A is True, R is False
D. A is False, R is True
Ans: C. A is True, R is False
Q. Assertion: There is always interaction between ecosystem
Reason: An ecosystem is recognized as self-regulating and self-sustaining entity.
A. Both A and R are true and R is the correct explanation of A
B. Both A and R are true and R is not the correct explanation of A
C. A is True, R is False
D. A is False, R is True
Ans: A. Both A and R are true and R is the correct explanation of A
Section B
All Series
Ans: There is no change in the image distance when we increase the distance of an object from the eye.
This is because the image is always formed at the retina.
Q. Why cannot we read a printed page by holding it very close to our eyes. Why?
Ans: Our eyes have the power of accommodation in which the focal length of our eye lens adjusts according to the object distance.
Our eye lens cannot adjust if the object is less than 25 cm far from the eye. Hence we cannot read a page by holding it very close to our eyes.
Q. Write a balanced chemical equation for the following chemical reactions:
i. Barium Chloride + Aluminium sulphate -> Barium sulphate + Aluminium chloride
3 BaCl2 + Al2(SO4)3 -> 3 BaSO4 + 2 AlCl3
ii. Zinc carbonate -> Zinc Oxide + Carbon dioxide
ZnCO3 -> ZnO + CO2
Q. Let the resistance of an electric component remains constant while the potential difference across the two ends decreases to half. What changes will occur in the current through it?
Ans: When the resistance remains constant while the potential difference decreases to half, the current also reduces to half.
Q. Write the formula of Cyclopentane and draw its electron dot structure.
Ans: The Formula of Cyclopentane is C5H10
Q. Draw a pattern of magnetic field lines around a current carrying solenoid.
Ans:
Q. What would you observe when zinc is added to a solution of Iron (II) sulphate? Write a chemical reaction that takes place.
Ans: When Zinc is added to the iron sulphate solution, the zinc displaces iron to form Zinc Sulphate.
The reaction can be written as:
FeSO4 + Zn -> ZnSO4 + Fe
Q. How is the concentration of hydroxide ions affected when excess base is dissolved is a solution of sodium hydroxide?
Ans: We know that hydroxide ions (OH-) are produced when a base is dissolved in water.
When excess base is dissolved is a solution of sodium hydroxide, the concentration of hydroxide ions will increase.
Q. Under what soil conditions do you think a farmer would treat the soil of his fields with quick lime or slaked lime or chalk
Ans: When the soil has turned acidic due to the use of Fertilizers, pesticides, insecticides etc, the farmer would treat it with quick lime, slaked lime or chalk.
This neutralizes the acidity of soil.
Q. How does our body respond when adrenaline is secreted into our blood?
Ans: Adrenaline is a rush hormone. When it is secreted into our blood, It increases the heart beat and breathing rate. It also dilates the blood vessels.
Section C
All Series
Q. The potential difference between the terminals of an electric heater is 60V when it draws a current of 4 A from a source. What current will the heater draw if the potential difference is increased to 120 V?
Ans: Given,
Potential difference = 60 V
Current = 4 A
Thus, Resistance(R) = V/I
R = 60/4
R = 15 Ohm.
Therefore resistance of heater is 15 Ohm.
Now, When Potential difference is increased to 120 V, the current will also increase but the resistance will remain same.
Thus New Current (I) = V/R
I = 120/15
I = 8 A
Therefore, 8A current will flow when Potential difference is increased to 120V.
Q. An electric heater of resistance 20 ohm takes current of 5 A. Calculate the heat developed in 30 seconds.
Ans: Given,
Resistance (R ) = 20
Current (I) = 5 A
Time = 30 s
We Know,
Heat developed (H) = I^2 x R x T
H = 5 x 5 x 20 x 30
H = 15000 Joules.
Thus, heat developed in the circuit will be 15000 joules.
Q. Define Magnetic Field. List any three sources of Magnetic field.
Ans: Magnetic field is the space around a magnetic material where it exerts its magnetic force.
It is represented in the form of magnetic field lines.
The three sources of magnetic field are bar magnet, solenoid, current carrying conductor.
Q. What is Electromagnet? State two points of difference between electromagnet and a permanent magnet
Ans: An electromagnet is a temporary magnet which acts as a magnet as long as electricity passes through it e.g. Solenoid
The three sources of magnetic field are bar magnet, solenoid, current carrying conductor.
Q. What is Electromagnet? State two points of difference between electromagnet and a permanent magnet
Ans: An electromagnet is a temporary magnet which acts as a magnet as long as electricity passes through it e.g. Solenoid
|
Electromagnet |
Permanent
magnet |
|
It is made of
soft iron |
It is made of
hard iron |
|
Its strength
can be changed |
It has fixed
strength |
|
It is
temporary magnet |
It is
permanent magnet |
|
E.g Solenoid |
E.g Bar
magnet |
Q. Differentiate between combination reaction and decomposition reaction with the help of examples
Ans:
|
Combination
Reaction |
Decomposition
Reaction |
|
Two or more
reactant form single product |
A single
reactant forms two or more products |
|
They are
usually exothermic |
They are
usually endothermic |
|
e.g 2Mg + O2
-> 2 MgO |
e.g. CaCO3
-> CaO + CO2 |
Q. What is a balanced chemical equation? Why should chemical equation be balanced?
Ans: A balanced chemical equation is one that has the same number of atoms of each element in the reactants as in the products.
The chemical equation needs to be balanced so that it follows the law of conservation of mass so that mass of products should be equal to mass of reactants.
Q. Differentiate between minerals and ores with the help of examples.
Ans:
|
Mineral |
Ore |
|
Minerals are
natural substances that occur inside the earth. |
Ore are
minerals from which metal can be extracted |
|
All minerals
are not ores |
All ores are
minerals |
|
Example:
Salt, Clay, Marble |
Example:
Bauxite, Hematite, Rock salt. |
Q. In the electrolytic refining of metal M, what would you take as the anode, the cathode and the electroyte?
Ans: Electrolytic refining is the method for the refining and purifying of metals.
During electrolytic refining, the impure metal is taken as anode, the pure metal is taken as cathode and the metal salt is taken as electrolyte.
Q. What advantages over an aquatic animal does a terrestrial organism have with regard to obtain oxygen for respiration?
Ans: Terrestrial organisms take up oxygen from the atmosphere whereas aquatic animals obtain oxygen dissolved in water. Air contains more O2 as compared to water. Since the content of O2 in the air is high, terrestrial animals do not have to breathe faster to get more oxygen.
Q. Differentiate between aerobic and anaerobic respiration. Name two organisms that use anaerobic mode of respiration.
Ans:
|
Aerobic
Respiration |
Anaerobic
Respiration |
|
It occurs in presence
of Oxygen |
It occurs in absence
of Oxygen |
|
Complete
breakdown of Glucose occurs |
Incomplete
breakdown of Glucose occurs |
|
CO2 and H2O
are formed as end product |
Ethanol or
Lactic acid are formed as end product |
|
It releases
more energy |
It releases
less energy |
The two organisms in which anaerobic respiration occurs are yeast and some bacteria such as Lactobacillus, E.Coli.
Q, Write the function of each of the following components of transport system in human beings?
i. Blood Vessels ii. Blood Platelets
Ans: Blood Vessels: Blood vessels are of many types such as Arteries, Veins, Cappilaries. They carry blood from heart to the body and back.
Blood Platelets: Blood platelets are also called thrombocytes. They help in the clotting of blood.
Q. Why do herbivores have longer whereas carnivores have shorter small intestines?
Ans: Herbivores have longer intestines than carnivores because they eat food which is rich in cellulose which takes longer time to digest.
Q. What would be the consequences of deficiency of haemoglobin in our bodies?
Ans: Haemoglobin is found inside the RBC’s in the blood and carries oxygen to the body parts. If there is deficiency of haemoglobin in our bodies, sufficient amount of oxygen will not reach to the body parts.
Q. Give the points of difference between autotrophic and heterotrophic nutrition?
Ans:
Autotrophic
Nutrition | Heterotrophic
Nutrition |
Organisms prepare
their own food | Organisms
depend on others for food |
They are
called producers | They are
called consumers |
They can be
photoautotrophic or chemoautotrophic | They can be
holozoic, saprotrophic or parasitic |
e.g Green
plants, Blue green algae, Euglena | e.g All
animals, fungi etc |
Q. Some diabetic patients are treated by giving insulin injections. Why?
Ans: Diabetic patients are given insulin injections because their pancreas cannot produce its own insulin.
Insulin lowers blood sugar level.
Q. Which animal or plant hormone is associated with following:
i. Develop secondary sexual characters at puberty in boys
ii. Inhibits growth in plants
iii. Goitre
Ans:
i. Develop secondary sexual characters at puberty in boys
Ans: Testosterone
ii. Inhibits growth in plants
Ans: Abscisic Acid
iii. Goitre
Ans: Thyroxine
Q. Chances of fertilization are more if copulation has taken place during the middle of menstrual cycle. Give reasons.
Ans: Fertilization is the process of fusion of sperm and egg to form zygote.
The chances of fertilization is more if copulation has taken place in the middle of menstrual cycle because the egg is present in the fallopian tube where the fertilization occurs.
Q. Give reasons for the following:
i. Petals of flowers are variously coloured
ii. Some plants are propagated only by vegetative methods.
Ans:
i. Petals of flowers are variously coloured
Petals of flowers are variously coloured in insect pollinated and bird pollinated flowers so that it can attract insects and birds from distances.
ii. Some plants are propagated only by vegetative methods.
Ans: Some plants are propagated only by vegetative methods such as through stem, root or leaf because they do not produce viable seeds.
E.g. Banana, Bryophyllum, Potato etc.
Q. How do Mendel’s experiments show that the traits are inherited independently?
Ans: Mendal proved that traits are inherited independently on basis of dihybrid cross. He selected dominant Plant with Round and Yellow seeds (RRYY) and recessive plant with Wrinkled Green Seeds (rryy) .
The F1 generation had Round and Yellow seeds (RrYy).
Upon selfing the F1 generation, two new recombinant forms were produced besides two parental forms in the ratio of 9:3:3:1.
It showed the genes assort independently of each other.
Q. What factors could lead to rise of new species?
Ans: The factors that could lead to rise of new species are:
1. Isolation: When individuals of particular species are isolated geographically or reproductive. This leads to formation of new species.
2. Mutation: Mutation in genes may lead to formation of new species.
3. Genetic drift.
4. Natural selection.
Q. What are the different ways in which individuals with a particular trait may increase in a population?
Ans: The different ways in which individuals with a particular trait may increase in population are as under:
1. Reproduction: When individuals of particular trait get more chances of reproduction, their population increases.
2. Natural selection: Nature favours individuals of particular trait to survive and reproduce.
3. Genetic drift: In genetic drift, A section of species dies of natural calamity.
In genetic drift, A trait which is present in less population is likely to perish.
Q. Will geographical isolation be a major factor in the speciation of an organism that reproduces asexually? Why or why not
Ans: No, geographical isolation will not be a major factor in the speciation of an organism that reproduces asexually.
This is because these organisms involve single parent where replication of DNA occurs. There is no variation as well.
Q. How can you help in reducing the problem of waste disposal at local level? Give any two methods
Ans: The waste can be managed by various methods at local level:
1. Landfills: The waste is buried in low lying areas or huge pits.
2. Incineration: The waste is burned at high temperature and converted into ashes.
3. Recycling of waste: Paper, plastic, metals can be recycled to be used again.
4. Compost: The organic waste is collected in compost pit where it decays to form manure.
Q. What are the problems caused by the non biodegradable wastes that we generate?
Ans: Non Biodegredable waste is the type of waste which cannot be decomposed by the bacteria and fungi e.g. Plastic, Polythene, Metals etc.
Biodegredable waste pollutes the environment
They make the soil infertile
It remains in the environment for long period of time.
Section D
All Series
i. Between Centre of Curvature and Principal focus of concave mirror
ii. At the focus of concave mirror
iii. Between focus and pole of the concave mirror
Ans:
Q. An object of size 7.0 cm is placed at 27 cm Infront of a concave mirror of focal length 18 cm. At what distance from the mirror should a screen be placed so that a sharp focused image can be obtained? Find the size and the nature of the image
Ans: Given,
U = - 27 cm
H = 7 cm
F = - 18 cm
We Know,
1/V + 1/U = 1/F
1/V + (-1/27) = -1/18
1/V - 1/27 = -1/18
1/V = -1/18 + 1/27
1/V = -3 + 2 /54
1/V = -1/54
V = - 54 cm
Therefore, the screen should be placed 54 cm far from the mirror to obtain sharp image.
To know the size of Image, we know
H’/H = - V/U
H’/7 = - (-54)/-27
H’ = - 2 * 7
H’ = -14 cm.
The image will be 14 cm long. The minus sigh indicates that the image will be inverted and real
Q. Draw the structure of
i. Bromo pentane
ii. Hexanal
iii. Propene
iv. 2,3- Dimethyl Butane
v. 2 Propanol
Ans:
.png "JKBOSE Science Solved Paper")
Q. Explain the following reactions with examples:
i. Combustion reaction
ii. Substitution reaction
Ans:
i. Combustion Reaction: The carbon and its compounds react with oxygen to produce carbon dioxide, water and large amount of heat and light.
Examples:
CH4 + 2 O2 ------> CO2 + 2 H2O
ii. Substitution reaction: When chlorine is added to hydrocarbons. It replaces hydrogen atoms. The reaction is substitution reaction.
Example:
CH4 + Cl2 _____> CH3Cl + HCl
Q. Describe the structure and functioning of Nephron?
Ans: Nephron is functional unit of kidney and helps to remove wastes from body. There are about 1 million nephons in each kidney.
Each nephron is about 3 cm long.
Nephron consists of following parts:
A. Malphigian body
B. Renal tubule
C. Collecting duct
A. Malphigian body:
It contains glomerulus and bowmans capsule.
Glomerulus is bunch of capillaries.
Bowmans capsule is cup shaped having capsular space.
B. Renal tubule:
Renal tubule consists of follwing parts:
Proximal convulated tubule,
Loop of henel
Distal convulated tubule
C. Collecting duct: The wastes, salts and extra water get collected in collecting duct.
Functioning of Nephron: The urine formation occurs in nephrons.
It occurs in following steps;
1. Filteration
2. Reabsorption
3. Secretion
1. Filteration: It occurs in glomerulus.
Walls of glomerulus are thin so substances such as ions, water, creatinine, urea, glucose pass into bowmans capsule.
2. Reabsorption: It occurs in renal tubule
Some substances such as glucose, ions extra water enter back into blood.
3. Secretion: It occus in renal tubule.
Some substances such as creatinine, potassium ions, Ammonia are secreted from blood into urine.
Q. Describe the transport of the following materials in plants:
i. Water ii. Minerals iii. Food
Ans:
Water and Minerals: Water and minerals are transported in plants through xylem.
The process is called ascent of sap.
The sap is absorbed by root hairs by osmosis. It is then transported into cortex cells and xylem.
The sap then moves up the plant by transpiration pull, cohesion and adhesion.
Food: The food is made in leaves of plants by the process of photosynthesis.
The food is then transported to other parts of plant through phloem and the process is called translocation.
.......................................................................................................................................................................
