CBSE Pathshala

[Practice Paper] LESSON-7 (Combustion and Flame)  LESSON-9(Crop Production and its Management) LESSON-20 (Pollution of water) 2 marks Questions :- Q1 What is a fuel? Give examples Q2 What are combustible materials? Q3 When we boil water in paper cup, the cup does not catch fire. Why? Q4 Define ignition temperature. What is the ignition temperature of White Phosphorus? Q5 What happens when a matchstick is striked against the matchbox? Q6 Flame of a burning candle goes off, when we blow over it strongly. Give suitable reason. Q7 Differentiate between Rapid and Spontaneous Combustion. Q8 Why does a small piece of Sodium or White Phosphorus catch fire in air? Q9 What precautions should be taken at LPG godowns or petrol pumps? Q10 If a person’s cloth catches fire, how can you put it off? Q11 What are the harmful effects of incomplete combustion? Q12 How is acid rain harmful? Q13 Define Explosive Combustion with examples...

LESSON -1 (The Cell – Its structure and Functions) [Source:DAV Ballabhgarh] LESSON -2 (Microorganisms : Friends or Foes ) NOTE—Q.no.1 to 30 carry two marks each.Q.no.31 to 35 carry three marks each. Q.1 Differentiate between chloroplasts and chromoplasts. Q.2 Why were the cells remained undiscovered for a long time? Q.3 Name the unit used to express cell size. Express its value in metres. Q.4 What is the function of albumen and yolk in an egg? Q.5 What is the composition and function of cytoplasm? Q.6 Describe the structure of nucleus. Q.7 What is the importance of cilia and flagella ? Q.8 Describe the various levels of organization. Q.9 Why do plant cells have cell wall? Q.10 Classify the living organisms on the basis of the cell number. Q.11 What advantage does amoeba derive by changing shape? Q.12 A hen’s egg can be seen easily. Is it a cell or a group of cells? Give reason. Q.13 Are the cells in an elephant larger than the cells in a rat? Justify your answer. Q.14 Why do vaccum p...

Q.1. What is heredity? Ans:- Heredity refers to the transmission of characters or traits from the parents to their offspring. Q.2. Name the plant on which Mendel performed his experiments? Ans:- Garden Pea ( Pisum sativum .) Q.3. Define variation? Ans:-Variation refers to the differences in the characters or traits about the individuals of a species. Q.4. Define a gene? Ans:- Gene is a small segment of DNA on a chromosome occupying specific position in which is a hereditary determinant or unit of a biological function. Q.5.Write the expanded form of DNA? Ans:- DNA - Deoxyribonucleic Acid. Q.6. What are the components of chromosome? Ans:- Each chromosome is double or replicated and consists of two thread like structures called chromatids attached to each other at centromere. .Each chromatid has a number of dense areas arranged linearly which are known as chromomeres. They represent the areas of active genes. .Internally each chromosome has two spirally coiled ...

8 th Science: Chapter:  Reproduction and Reaching of adolescence 1. How are human twins produced? Ans: There are two way twins are formed. (a) Twins occur when a single egg is fertilized to form one zygote which then divides into two separate embryos.(b) Twins occur when two separate eggs  are fertilized by two separate sperm. 2. Whose sex chromosomes is responsible for sex of unborn baby, either father’s or mother’s sex hormones. Ans: The sex chromosomes of the father determine the sex of an unborn baby. 3. Why ace and pimple appear in adolescent age of human being? Ans: This is because during puberty the secretion of sweat glands and sebaceous glands (oil glands) increases in the skin. 4. What is Adam’s apple? At puberty, the voice box or the larynx begins to grow. The growing voice box in boys can be seen as bump in the throat called Adam’s apple. 5. Why does reproductive age of women starts from menarche and end at menopause? Women start producing...

1. What are pathogens?[1] Ans. Disease-causing organisms are called pathogens 2. List any two human activities that lead to an increase in the carbon dioxide content of air.[1] Ans: a. Combustion of wood. b. Deforestation. c. Respiration 3. (a) Name any two green house gases. (b) What causes global warming?[2] Ans:  (a) Carbon dioxide (CO2), methane (CH4), ozone (O3) and water vapour (H2O) green house gases. (b) The greenhouse gases do not allow heat rays to escape from the earth resulting in an increase of temperature of the earth. Hence, green house gases cause global warming. 4. Give two examples each of biodegradable and non-biodegradable pollutants.[2] Ans: Biodegradable pollutants-cow dung and paper Non-biodegradable pollutants-polythene, plastic and DDT 5. Write two points of difference between gymnosperms and angiosperms.[2] Ans:   Gymnosperms    (i) The seeds are naked. (ii) The microspores and megaspores are produced by male and female c...

CBSE NCERT IX-Physics for term-II Chapter: Sound key points 1. Sound is a wave that is created by vibrating objects and propagated through a medium from one location to another.  2. A disturbance that travels through a medium, transporting energy from one location to another location is called wave. The medium is simply the material through which the disturbance is moving; it can be thought of as a series of interacting particles.  3. In our body Vocal cord is vibrating body that produce sound wave.  4. The sound wave is transported from one location to another by means of particle-to-particle interaction like air particles in air.  5. Air particles interact continuously throughout the entire medium that causes disturbance to its nearest neighbours till sound reach to listener.  6. A sound wave is a disturbance that is travel through a medium via the mechanism of particle-to-particle interaction. Hence sound wave is characterized as a mechanical wave....

JSUNIL TUTORIAL, BIHAR IX CH – SOUND QUESTIONS - 1 (Q)1. Fill in the blanks: (a) The loudness of sound is proportional to the _________ of the amplitude of the vibration. (b)The speed of sound __________as it moves from solid to gaseous state. (c) In any medium the speed of sound __________ with increase in temperature. (d) The distance between two consecutive compression or two consecutive rarefaction is called the ____. (e) The change in the density or pressure from a maximum value to minimum and then back to the maximum is called an ___________. (f) The number of periodic oscillations per unit time is called the ________ of the sound wave. (g) Sound is produced due to ________of different objects. (h). Sound travels as a _________ wave through a material medium. (i) Sound travels as successive _________ and ___________ in the medium. 2. Q. A person has a hearing range from 20 Hz to 20 kHz. What are the typical wavelengths of sound waves in air corresponding to these two frequenci...