CBSE Class 10 - Science Periodic Assessment -1 (2017) (#cbseNotes)

CBSE Class 10 - Science Periodic Assessment-1 (2017) 

Questions asked in the Q. Paper are from the following chapters:

1. Biology : Life Processes
2. Chemistry: Chemical Reactions and Equations
3. Physics: Electricity

CBSE Class 10 - Chemistry - 23 HOTS Questions on Chemical Reactions You Must Know - Q and A (#cbsenotes)

23 HOTS Questions on Chemical Reactions You Must Know

Class 10 - Chemistry - Q & A

Q1: A white coloured water insoluble substance X on reacting with dilute H₂SO₄ released a colourless and odourless gas accompanied by brisk effervescence. When the gas was passed through water, the solution obtained turned blue litmus red. On bubbling the gas through lime water, it initially became milky and milkiness disappeared when the gas was passed in excess. Identify the substance X‘. Write its chemical equations of the reactions involved.

Answer: Calcium carbonate on reacting with dilute sulphuric acid releases a colourless and odourless gas carbon dioxide accompanied  by brisk effervescence.

The chemical equation for this reaction is
CaCO₃ + H₂SO₄ → CaSO₄ + H₂O + CO₂

Ca(OH)₂(aq) + CO₂(g) → CaCO₃(s) + H₂O(l)
milky

CO₂ (g) + CaCO₃ (s) + H₂O (l) ⇌ Ca(HCO₃)₂ (aq)
(colourless)



Q2: Ahmad took a magnesium ribbon (cleaned) and burned it on a flame. The white powder formed was taken in a test tube and water was added to it. He then tested the solution formed with red and blue litmus paper. What change was seen? Why?


Answer:
⒜ Red litmus paper turned blue.
⒝ Blue litmus paper remained blue.

This is because the magnesium ribbon on burning in air forms the white magnesium oxide. MgO when dissolves in water, it forms magnesium hydroxide, which is basic in nature.

2Mg + O₂ → 2MgO

MgO + H₂O → Mg(OH)₂ (aq) + H₂(g)

CBSE Class 10 - Physics - Electricity - (Holiday Assignment) (#cbseNotes)

Electricity - (Holiday Assignment)

Q1: Two metallic wires A and B of same material are connected in parallel. Wire A has length l and radius r and wire B has length 2l and radius 2r. Compare the ratio of the total resistance of parallel combination and the resistance of wire A.

Answer:
Wire A:
Length = l
Radius = r
Area   = πr²
R₁   = ρ  x l /(πr²)

Wire B:
Length = 2l
Radius = 2r
Area = π(2r)² = 4πr²
R₂   = ρ  x 2l /(4πr²) = ρ  x l /(2πr²)

Let Rₚ = effective resistance of parallel combination
∴ 1/Rₚ = 1/R₁ + 1/R₂

1/Rₚ = (πr²)/ρl + (2πr²)/ρl

Rₚ = ρl/(3πr²)

CBSE Class 10 - Biology - Life Processes - 51 Questions You must Revise (#cbseNotes)

LIFE PROCESSES
51 Questions You must Revise

(Revision Questions based on NCERT Chapter)

Q1: Define nutrition.

Q2: Is the presence of only one life process sufficient to decide whether an object is living or non-living?

Q3: Explain the types of heterotrophic nutrition on the basis of food habit.

Q4: What is the role of iodine solution in activity 6.1?

Q5: Give scientific reason. Unwanted and harmful waste products need to be eliminated from the body.

Q6: What is the role of KOH in activity 6.2?

Q7: What is the function of pancreas in human digestive system?

CBSE Class 10 - Biology - Life Processes (Holiday Assignment) Q & A (#cbsenotes)

Life Processes 

(Assignment Q & A) 

Structure Of Leaf
credits: Zephrys, undr CCAS 3.0, Wikimedia Commons

Q1. Where are chloroplasts present in the leaf?

Answer: Below the epidermis, there are layers of palisade cells that contain chloroplasts.


Q2.  Name the pigments that can absorb solar energy. Also name the enzyme required for photosynthesis.

Answer: Chlorophyll. RuBisCo (Ribulose-1,5-bisphosphate carboxylase/oxygenase), a protein enzyme is required to initiate photosynthesis.

(Note: RuBisCo is the most abundant protein in the world due to its presence in green plants.)


Q3. Name one organism each having saprophytic and parasitic and holozoic nutrition.

Answer:
Saprophytic: Mushroom, yeast
Parasitic: Cuscutta (Dodder plant), Ring Worm, Leech
Holozoic: Human, amoeba


Q4. Enlist two functions of bile juice of liver.

Answer:
1. Bile neutralized the acidic medium of food coming from stomach and  makes it alkaline.
2. It breaks the large fat globules into smaller ones, this increases the enzyme action.

CBSE Class 10 - Science - CH 14 Sources of Energy (Important Differences) (#cbseNotes)

Sources of Energy (Important Differences) 

Fossil Fuels Energy vs Solar Energy

	Fossil Fuels Energy	Solar Energy
1.	Fossil energy can be used day or night.	Can be used in day time. We need to store its energy to use it at night.
2.	The stock of fossil energy is limited. e.g. coals will last for next 200 years.	Sun’s energy is unlimited.
3.	Fossil energy is non-renewable. It takes millions of year to produce fossil fuel.	Solar energy is renewable source of energy.
4.	Give pollution.	Pollution Less
5.	Fossil fuels release energy when they are burnt in air.	Solar radiation carry packets of energy due to fusion reaction in the sun.

CBSE Class 10 Chemistry - CH2 Acids and Bases - Very Short Questions and Answers (#cbsenotes)

Acids and Bases  

Very Short Questions and Answers

Class 10 Science - Chemistry

Q1: What is an acid?

Answer: Acid is a compound which yields hydrogen ions (H⁺) or Hydronium (H₃O⁺) ions , when dissolved in water.


Q2: What is the pH value of acids?

Answer: Less than 7 (i.e. 0 to < 7)


Q3: What is the taste of acids?

Answer: Sour


Q4: What happens to blue litmus paper when it comes in contact with acid solution?

Answer: It turns into red.


Q5: On the basis of origin, how acids are classified as?

Answer: Organic acids and Mineral acids.

CBSE Class 8/10 - Metals vs Non-Metals (Comparison) (#cbseNotes)

Metals vs Non-Metals

Physical Properties Comparison

Property	Metals	Non Metals
Physical State	Most metals are solids at room temperature except mercury which is a liquid. Gallium and Cesium also changes into liquid at slightly above room temperature.	Non Metals exist in all states. Eleven are gases, bromine is liquid while others are solids.
Melting and Boiling Point	Generally have high melting and boiling points. (Exceptions are Gallium, Mercury, Sodium and Potassium.)	Generally they have low melting and boiling points. Exceptions are: Carbon, Boron and Silicon.
Density	They have high density except Sodium and potassium.	Low denisty (Diamond is an exception.)
Lusture	Metals shine and are lustrous.	Non-metalls appear dull. (Exceptions are Diamond, graphite and iodine.)

CBSE Class 10 - Biology - Digestive Organs and Their Functions (#cbsenotes)

Digestive Organs and Their Functions

CBSE Class 10 - Physics - Electricity - Important Points To Remember (#cbsenotes)

Electricity - Important Points To Remember 

CBSE Class 10 - Physics 

① Electric current is defined as the amount of charge flowing through a particular cross section area in a unit time.


② The SI unit of electric current is ampere.


③ A stream of electrons moving through a conductor constitutes an electric current. In a conventional current, the direction of current is taken opposite to the direction of flow of electrons i.e. flow of positive charges from +ve terminal to -ve terminal.


④ 1 A is the flow of 6.25 × 10¹⁸ electrons per second, or 1 coulomb per second.

CBSE Class 10 - Chemistry - Chapter 1 - Chemical Reactions and Equations (#cbsenotes)

Chemical Reactions and Equations 

CBSE Class 10 - Chemistry - Chapter 1 

Worksheet on Balancing Chemical Equations

Question: Balance the following chemical equations.

⒜ Al(s) + Fe₂O₃(s) ---⤑  Al₂O₃(s) + Fe(s)

⒝ Na(s) + H₂O ---⤑ NaOH + H₂

⒞ NH₃(g) + O₂(g) ---⤑ NO(g) + H₂O(g)

⒟ Fe(s) + H₂O(g) ---⤑  Fe₃O₄(s) + H₂(g)

⒠ NaOH + H₂SO₄ ---⤑  Na₂SO₄ + H₂O

⒡ Hg(NO₃)₂ + KI ---⤑ HgI₂ + KNO₃

CBSE Class 10 - Biology - Life Processes (Nutrition) - Q and A (#cbsenotes)

Life Processes (Nutrition)  

Q and A

CBSE Class 10 - Biology 

Q1: Define nutrition.

Answer: The process of taking in food or consuming food and utilising it is called nutrition.


Q2: What are the modes of nutrition?

Answer:
① Autotrophic
② Heterotrophic


Q3: What is a nutrient?

Answer: A nutrient is a substance in food that performs a physiological function in the body. A nutrient gives energy and promotes growth and development of the body.


Q4: What happens if there is a deficiency of a particular type of nutrient? Give an example.

Answer: There may be a deficiency disorder. e.g. deficiency of Vitamin C causes capillaries break easily and often leads to bleeding of gums.


Q5: Name the different classes of nutrients.

Answer: Carbohydrates, Lipids, Proteins, Minerals, Vitamins and Water.

CBSE Class 10 - SA2 Science Sample Question Paper (2016-17)(#cbsepapers)

CBSE Class 10 - SA2 Science Sample Question Paper (2016-17)

☛See Solutions here.

CBSE Class 10 - Pre SA2 Science Sample Question Paper (2016-17)(#cbsepapers)

CBSE Class 10 - Pre SA2 Science  Sample Question Paper (2016-17)

CBSE Class 10 - Physics - The Human Eye and Colourful World (Very Short Q and A)(#cbsenotes)

The Human Eye and Colourful World

Very Short Q and A


Question 1: Name the essential parts of a human eye.

Answer: Cornea, Iris, Pupil, eye lens, ciliary muscles and retina.


Question 2: What is cornea??

Answer: Spherical membrane covering the front of the eye


Question 3: Which liquid fill the space behind the cornea?

Answer: Aqueous humour


Question 4: Which liquid fills the space between lens and retina?

Answer: vitreous humour


Question 5: How is the eye lens held in its position?

Answer: By Ciliary muscles which hold the eye in position.

CBSE Class 10 - Marking Scheme Of SA2 Science Sample Question Paper (2016-17)(#cbsepapers)

CBSE Class 10 - Marking Scheme Of (SA2) Science Sample Question Paper (2016-17)

☛See Science Sample Question Paper (2016-17)

CBSE Class 10 - Science Sample Question Paper (2016-17) (#cbsepapers)(#cbsenotes)

CBSE Class 10 - Science Sample Question Paper (2016-17)

☛See also Marking Scheme of SA2 Science Sample Question Paper (2016-17)

CBSE Class 10 - Science Pre-board SA2 Sample Question Paper (2016-17)

CBSE Class 10  - Science Pre-board SA2 Sample Question Paper (2016-17)

CBSE Class 10 - Science - Management of Natural Resources - Very Short and Short Q and A (#cbsenotes)

Management of Natural Resources 

Very Short and Short Q and A from CBSE Papers 


Q1: What is coliform ?

Answer: It is a group of bacteria found in human intestine.


Q2: List any four stakeholders which may help in the conservation of forests.

Answer: People, the government, industrialists and Wildlife and nature enthusiasts.


Q3: What is reuse strategy ? Reuse strategy is considered better than the recycling strategy. Why ?

Answer: In reuse strategy, things are used again and again instead of throwing them. It is better than recycling of objects as no energy is used in this strategy for remaking of objects.


Q4: India has more than 50,000 strains of rice. Mention the level of biodiversity it represents.

Answer: It is a genetic variation within the species.


Q5: What do the three R’s refer to save the environment ? Which one of these would be the best for environment ?

Answer: Three R’s refers to Reduce, Recycle and Reuse.
Reducing wastage of energy is the best for environment.

Class 10 - Biology - How Do Organisms Reproduce? - Worksheet

Reproduction 

Longitudinal Section of a Bisexual Flower
Label the parts of the flowers (answer given in this post)
image credits: wikimedia

Worksheet

Fill in the blanks


1. In _________, many bacteria and protozoa simply divide into two or more daughter cells.


2. __________ is associated with the stability of population of species.


3. The fertilized egg gets implanted in the lining of the ________.


4. In mammals, the embryo gets nutrition from the mother’s blood with the help of a special tissue called _________.