Note: The below solutions have been prepared in simple and concise language to suit my Govt School children and have also been added to the Notes of respective units wherever necessary!
.png "JKBOSE Class 10th Biannual 2023 Solved Science Paper") |
| JKBOSE Class 10th Biannual 2023 Solved Science Paper, Mufawad |
LIGHT
Q. The image formed by a concave mirror is observed to be virtual, erect and larger than the object. Where should be the position of the Object?Ans: The object should be placed between Pole (P) and Focus (F) of the concave mirror.
Q. There is a Spherical mirror having the radius of curvature of 20 cm. What is its focal length?
Ans: The focal length is half of the radius of curvature. Therefore, Radius of curvature will be 10 cm.
Q. Absolute refractive index of Kerosene, turpentine and water are 1.44, 1.47 and 1.33 respectively. In which of these does light travel fastest?
Ans: The speed of light is inversely proportional to the refractive index. Therefore, the light travels fastest in water which has lowest refractive index of three.
Q. A ray of light traveling in air enters obliquely into water. Does the light ray bend towards the normal or away from the normal?
Ans: Since the ray of light is travelling from rarer to denser medium. Therefore, it will bend towards the normal.
Q. What are the rules for the formation of images by a concave lens? Draw appropriate ray diagrams to illustrate these rules?
Ans:
The rules used for drawing ray diagrams for the formation of an image by a concave mirror are:
Rule 1: If the incident ray is parallel to the principal axis then the reflected ray passes through the focus of the concave mirror.
Rule 2: If the incident ray passes through the focus of the concave mirror, the reflected ray is parallel to the principle axis.
Rule 3: If the incident ray passes through the Centre of curvature of the concave mirror, the reflected ray traces the same path.
Q. A concave lens has focal length of 20 cm. At what distance from the lens a 5 cm tall object be placed so that it forms an image at 15 cm from the lens ? Also find the size of image formed.
Sol: Given,
F = - 20
V= - 15
U = ?
H= 5
We Have,
1/V – 1/U = 1/F
1/-15 - 1/U = 1/-20
-1/U = 1/-20 + 1/15
- 1/U = -3 + 4/ 60
-1/U = 1/60
U = - 60
Minus Sign indicates that object is placed on left of the lens, which always is the case.
Now, Magnification =
H’/5 = -15/-60
H’ = 1.25 cm.
Plus sign indicates that the image is erect and virtual.
Human Eye and the colourful World:
A. Red colour is least scattered B. Blue colour is least scattered
C. Red Colour is most scattered D. All colours are equally Scattered
Ans: A. Red colour is least scattered
Q. A student has difficulty in reading blackboard while sitting in the last row. What could be the defect the child is suffering from? How can it be corrected?
Ans: Since the child cannot see the blackboard clearly, she/he is suffering from 'myopia' or 'short - sightedness'.
Q. Draw the labelled diagram of human eye
Ans:
Electricity
Ans: Resistivity does not depend on the length of the conductor. Hence, doubling the length will not change its resistivity.
Q. Will current flow more easily through a thick wire or a thin wire of a same material, when connected to the same source? Why?
Ans: Current will flow more easily through a thick wire because the resistance is inversely proportional to the area of cross-section of the wire. Which means when the area of cross section of the wire increases then resistance will decrease.
Q. When a 12V battery is connected across an unknown resistor, there is a current of 2.5 mA in the circuit. Find the value of the resistance of the resistor.
Ans: Resistance (R) of a resistor is given by Ohm's law as,
V = IR
i.e.; R=V/I
Where, potential difference, V = 12 V
Current in the circuit, I=2.5mA=2.5×10−3A
R=12/2.5×10−3
=4.8×103Ω
=4.8kΩ
Therefore, the resistance of the resistor is 4.8 kΩ.
Magnetic Effects of Current:
A. The field consists of straight lines perpendicular to the wire
B. The field consists of straight lines parallel to the wire
C. The field consists of concentric circles centred on the wire
D. Both A and B
Ans: C. The field consists of concentric circles centred on the wire
Q. Every current carrying conductor produces magnetic field, this phenomenon was discovered by:
A. Maxwell B. Oersted C. Faraday D. Coulomb
Ans: Oersted
Q. The direction of magnetic field around a current carrying straight conductor can be determined by:
A. Flemings right hand rule B. Flemings left hand rule
C. Faradays Rule D. Right hand thumb rule
Ans: Flemings right hand rule
Q. The magnitude of magnetic field produced by a current carrying straight conductor is:
A. Directly proportional to the Intensity of current
B. Directly proportional to the distance from conductor
C. Inversely proportional to distance from the conductor
D. Both A and C
Ans: D. Both A and C
Q. If the direction of electric current in a current carrying conductor is upwards, the direction of magnetic field lines will be:
A. Clock wise B. Anticlockwise C. Both A and B D. Can’t be determined
Ans: B. Anticlockwise
Sources of Energy
Ans: There are very dangerous consequences of increasing demand of energy on environment. It leads to pollution, deforestation and global warming.
Steps to reduce energy consumption:
> We should use these resources in optimum.
> We should not waste the energy.
> We should use alternate source of energy such as solar energy.
Chemical Equations and Reactions
Ans: Fe+CuSO4→Cu+FeSO4
Q. Reaction of Zinc with dilute Sulphuric acid is:
A. Displacement reaction as well as Redox reaction
B. Precipitation reaction as well as Redox reaction
C. A redox reaction as well as Double displacement reaction
D. A decomposition reaction as well as combination reaction.
Ans: A. Displacement reaction as well as Redox reaction
Q. Assertion: When we mix the solution of sodium sulphate and barium chloride, White precipitate is formed.
Reason: The white precipitate of barium sulphate and that is formed by the reaction of SO4 2- and Ba2+
(a) Both, A and R, are true and R is the correct explanation of A
(b) Both, A and R, are true but R is not the correct explanation of A
(c) If A is true but R is false
(d) If A is false but R is true
Ans: (a) Both, A and R, are true and R is the correct explanation of A
Q. Translate the following statements into chemical equations and balance them:
i. Hydrogen gas combines with nitrogen to form ammonia
Ans: 3H2 + N2 → 2NH3
ii. Barium chloride reacts with aluminum sulphate to give aluminium chloride and barium sulphate.
Ans: BaCl2 +Al2(SO4)3 → AlCl3 +BaSO4
iii. Potassium metal reacts with water to give potassium hydroxide and hydrogen gas
Ans: 2K +2H2O → 2KOH +n H2
Q. An element reacts with oxygen to give a compound with a high melting point. The compound is soluble in water. The element is likely to be:
a. Calcium b. Carbon c. Silicon d. Iron
Ans: Calcium
Hint: Calcium reacts with oxygen to form calcium oxide (CaO), Also called Quick Lime.
Periodic Classification of Elements
A. Dobereiner’s triads B. Newlands law of Octaves
C. Mendeleev’s PT D. Modern PT
Ans: Mendeleev’s PT
Q. Which among the following is considered as the limitation of Mendeleev’s periodic table?
A. Prediction of New Elements B. Correction of atomic masses
C. Position of isotopes D. Both A and B
Ans: C. Position of isotopes
Q. Which of the following statements is not a correct statement about the trends when going from left to right across the periods of the Modern Periodic table?
A. The elements become less metallic B. The number of valance electrons increases
C. The atoms loose electrons more easily D. The oxides become more acidic
Ans: C. The atoms loose electrons more easily
Q. Arrange the following elements in the order of their decreasing metallic character:
Sodium Na, Silicon Si, Chlorine Cl, Magnesium Mg, Aluminium Al.
Ans: Since Metallic character decreases from Left to Right, Therefore,
Sodium Na > Magnesium Mg > Aluminium Al > Silicon Si > Chlorine Cl.
Carbon and its Compounds
Ans:
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Q. Draw the electron dot structure of Cyclopentane.
Ans:
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Q. Explain the following reactions with examples:
i. Oxidation reactions ii. Substitution reactions
Ans: The carbon and its compounds undergo Oxidation and Substitution.
A. Oxidation Reactions: Carbon and its compounds undergo oxidation reactions. In these reactions, compound of carbon react with oxidizing agents such as KMnO4 or K2Cr2O7.
Example:
C2H5OH + K2Cr2O7 −−−−−−−→ CH3COOH
B. Substitution Reaction: Carbon and its compounds undergo substitution reactions. In these reactions, Alkanes react with Halogens such as chlorine, bromine or Iodine which replaces Hydrogen atom from the alkane.
Example: CH4 + Cl -----> CH3Cl
Q. Write the IUPAC names of following compounds
Ans: i. Propanal
ii. 2-Butene
iii. 2 Bromo Propane
iv. 4 Pentanone
v. Propanoic Acid
Metals and Non Metals
A. Magnesium B. Silver C. Zinc D. Copper
Ans: Silver
Q. Why Platinum, Gold and Silver are used to make Jewellery?
Ans: They do not react with air and do not corrode easily. Upon that they are lustrous as well.
Q. Why Sodium, Potassium and Lithium are stored under the oil
Ans: Sodium, potassium, and lithium are very reactive metals and react vigorously with air as well as water. Therefore, they are kept immersed in kerosene oil in order to prevent their contact with air and moisture.
Acids, Bases and Salts
Ans: Sodium Carbonate also called Washing Soda is used for softening hard water.
Its formula is Na2CO3.
Q. Human body works within the PH range of:
A. 1.0 to 7.0 B. 7.0 to 14 C. 7.0 to 7.8 D. 7.8 to 9.8
Ans: C. 7.0 to 7.8
Hint: This question is factually incorrect. It probably is talking about blood with works in the range of 6.8 to 7.8. Some body parts have low pH such as Skin which has pH as low as 5.0
Q. There is a solution that turns red litmus blue. The pH of that solution is likely to be
A. 1 B. 5 C. 4 D. 10
Ans: 10
Q. An aqueous solution turns red litmus solution blue. Excess addition of which of the following solutions would reverse the change?
A. Baking Soda B. Lime C. Ammonium hydroxide D. Hydrochloric acid
Ans: D. Hydrochloric acid
Q. Which of the following gives the correct increasing order of acid strength?
Water (H2O) , Acetic Acid (CH3COOH), Hydrochloric Acid (HCl)
Ans: Hydrochloric acid is more acidic than Acetic acid which is more acidic than water.
Q. The pH value of a solution is lower, when:
A. The hydronium ion concentration is higher
B. the Hydronium ion concentration is lower
C. the hydroxide ion concentration is higher
D. the hydronium ion concentration is equal to hydroxide ion concentration
Ans: A. The hydronium ion concentration is higher
Life Processes
Ans: The lungs have alveoli which maximize the surface area for gaseous exchange.
The surface area of alveoli is about 70 sq. m which is much more than lungs.
Q. Explain the process of Photosynthesis in Plants. List four factors which influence this process.
Ans: Photosynthesis is a process in which green plants, blue green algae and protozoans like euglena use solar energy and convert it into chemical energy. Such organisms are also called autotrophs.
Equation:
6CO2 + 6H2O —> C6H12O6 + 6O2
It occurs in the chloroplasts of cells.
Process:
The process of Photosynthesis occurs in two steps:
1. Light Reaction: This reaction occurs during the day in the thylakoid membrane. In this phase, the light energy is converted to ATP and NADPH, which are used in the second phase of photosynthesis.
2. Dark Reaction: This reaction does not require day light and occurs in the stroma. In this phase, Glucose is formed from CO2. In this phase, the splitting of H20 takes place followed by reduction of CO2 to C6H12O6.
The four factors necessary for photosynthesis are:
Water: Absorbed from the soil by the roots
Carbon dioxide: Obtained from the atmosphere
Sunlight: Absorbed by chlorophyll molecules to split water molecules into hydrogen and oxygen
Chlorophyll: It is present inside the chloroplast in the cells.
Light intensity: Maximum photosynthesis occurs in blue light, and minimum in green light.
Carbon dioxide concentration: The higher the concentration, the higher the rate until a certain point.
Temperature: Increasing the temperature to a certain level increases photosynthesis. However, increasing the temperature above 40 °C reduces photosynthesis.
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.
Control and Coordination
Ans: The different types of Tropism are Phototropism, Geotropism, Hydrotropism, Chemotropism etc.
Q. How does chemical coordination occur in plants?
Ans: Chemical Coordination in plants occur through Phyto-Hormones. Phytohormones are chemical substances produced in plants which help in control and coordination in plants.
They are plant growth regulators. They include:
I. Auxins: They are found in shoot apex and young leaves.
They help in cell division and cell elongation. E.g. IAA, IBA
II. Gibberlins: They help in cell elongation and cell differentiation. E.g GA2, GA3
III. Cytokinins: They are found in endosperms and roots.
They help in cell division, cell elongation and breaking of dormancy.
IV. Abscisic acid: It acts as growth inhibitor.
It helps in promotion of dormancy, ageing of leaves.
Reproduction
Ans: Vegetative propagation is practiced because:
i. It is a quicker and less difficult way.
ii. It can aid plant growth in areas where germination has failed.
iii. It can be used to propagate plants that don't generate viable seeds or produce a small quantity of seeds.
iv. It's a quick way to grow a lot of plants in a short amount of time.
v. Potato tubers and ginger rhizomes are two examples.
Q. What is the role of Seminal vesicles in male reproductive system?
Ans: Seminal vesicles release secretions which help in Sperm motility, and supress immune activity in female reproductive tract.
Q. What is Puberty ? Name the hormones responsible for the production of secondary sexual characters in human beings?
Ans: Puberty is the age when an individual is getting mentally, physiologically and emotionally ready for reproduction. It is characterized by change in height, body shape, voice and development of sex organs.
Different hormones are responsible for production of secondary sexual characters in human beings, Such as:
Estrogen in females
Ans: Puberty is the age when an individual is getting mentally, physiologically and emotionally ready for reproduction. It is characterized by change in height, body shape, voice and development of sex organs.
Different hormones are responsible for production of secondary sexual characters in human beings, Such as:
Estrogen in females
Testosterone in males
Q. Discuss the structure of flower and draw a labelled diagram of longitudinal section of a flower?
Ans: The flower is reproductive part of plant. It has following parts.
Q. Discuss the structure of flower and draw a labelled diagram of longitudinal section of a flower?
Ans: The flower is reproductive part of plant. It has following parts.
I. Pedicel: It is the stalk of flower.
II. Thalamus: It is the broad base of pedicel.
III. Calyx (Sepals), It is outer whorl of flower. It is usually green in colour.
IV. Corolla: (Petals), It is inner whorl of flower. It is colourful and scented.
V. Androecium: (Stamen), It is male reproductive part of flower. It has flament, anther and anther lobes. The pollen grains are found inside anther lobes.
VI. Gynaecium: (Carpel), It is female reproductive part of flower. It has stigma, style and ovary.
Heredity and Evolution
Reason: Only useful variations are transmitted to the next generation.
(a) Both, A and R, are true and R is the correct explanation of A
(b) Both, A and R, are true but R is not the correct explanation of A
(c) If A is true but R is false
(d) If A is false but R is true
Ans: (d) A is false but R is true
Q. In evolutionary terms, can we say which among the bacteria, spiders, fish and chimanzees have a better body design? Why or Why not?
Ans: In evolutionary terms, chimpanzee has more complex body design.
The organism with better body design is one which has survived over long period of time and across different habitats.
Using that criteria, bacteria has simple but better body design.
Our Environment
Ans: Plastics and Polythene.
Q. A successful forest conservation strategy should involve
A. Protection of animals at highest level
B. Protection of consumers only
C. Protection of herbivores only
D. Protection of all physical and biological components
Ans: D. Protection of all physical and biological components
Q. Which factor is mainly responsible for increase in demand of natural resources?
A. Scientific advancement
B. Increase in population
C. Environmental pollution
D. Use of Biodegradable chemicals
Ans: B. Increase in population
Q. The important message conveyed by Chipko Movement is:
A. Ignore the community in forest conservation
B. Involve community in Forest conservation
C. To cut down forests for development
D. Govt agencies have the right to order destruction of trees
Ans: B. Involve community in Forest conservation
Q.Forests are called “Biodiversity hotspots”, because:
A. They provide food for rural people
B. Provide wood for construction
C. Protect us from hot weather
D. Host diverse range of living forms
Ans: D. Host diverse range of living forms
Q. The human activity that leads to the extinction of wildlife is:
A. Polluting the environment
B. Hunting the valuable wildlfe products
C. Introducing alien species
D. Alternation and destruction of natural habitat
Ans: D. Alternation and destruction of natural habitat
Q. Nowadays, we see the most of the material used in the marriage parties and other functions are non-biodegradable. Why is it necessary to replace these non-biodegradable items by disposable paper items?
Ans: It is very necessary to replace these non-biodegradable items by disposable paper items because they pollute land and water resources. They are also not decomposed by bacteria.
Q. In our day-to-day life we come across many items like polythene bags, vegetable peels etc. Make a list of at least seven items from your surroundings which are biodegradable.
Ans: Paper, Food waste, Human waste, Manure, Sewage sludge, dead animals and falling plant parts.
Management of Natural Resources:
Reason: Cultivation of land and grazing are allowed in national parks.
(a) Both, A and R, are true and R is the correct explanation of A
(b) Both, A and R, are true but R is not the correct explanation of A
(c) If A is true but R is false
(d) If A is false but R is true
Ans: (c) A is true but R is false
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