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You are provided with a mixture of naphthalene and ammonium chloride by your teacher. Suggest an activity to separate them with well-labelled diagram.

Naphthalene is insoluble in water but soluble in ether an organic solvent. It is volatile at room temperature Ammonium chloride... View Article

Which of the following feature will help you in distinguishing a plant cell from an animal cell? (a) cell wall (b) cell membrane (c) mitochondria (d) nucleus

a) Cell wall The cell is the fundamental unit of life. All the life activities are carried out by cells.... View Article

In coastal area, wind current moves from the sea towards the land during the day; but during the night it moves from land to the sea. Discuss the reason.

In coastal areas, during daytime, there is a regular flow of cool air from the sea towards the land. At... View Article

Which of the following is a recently originated problem of environment? (a) Ozone layer depletion (b) Greenhouse effect (c) Global warming (d) All of the above

d) All of these Explanation Ozone layer depletion The ozone layer is a region in the earth’s stratosphere that contains... View Article

Increased concentration of nitrogen in the air is believed to cause global warming. (True or False). Also write the false statements in their correct form.

False. An increase in the CO2 in the air is the cause of global warming. There are various causes of... View Article

The main function of abscisic acid in plants is to (a) increase the length of cells (b) promote cell division (c) inhibit growth (d) promote the growth of stem

c) Inhibit growth Explanation Abscisic acid (ABA) is a plant hormone. ABA capacities in many plant formative cycles, including seed... View Article

A synthetic fibre which looks like silk is obtained by chemical treatment of wood pulp. It is, therefore, known as artificial silk. What is its common name?

Rayon is obtained by the chemical treatment of wood pulp or cellulose. A synthetic fibre that looks like silk is... View Article

Difference Between Encoder and Decoder

Encoder Vs. Decoder: What is the Difference Between Encoder and Decoder? Encoder and Decoder are combinational logic circuits. One of... View Article

Classify the following crops into Kharif and Rabi crops and write in the tabular column given below: Maize, paddy, mustard, pea, gram, wheat, groundnut, cotton.

Kharif: Maize, paddy, groundnut, cottonRabi : Mustard, pea, wheat, gram Kharif crops The crops that are sown in the rainy... View Article

Two green plants are kept separately in oxygen-free containers, one in the dark and the other in continuous light. Which one will live longer? Give reasons.

The plant which is kept in continuous light will live longer. We know that plant release carbon dioxide during respiration.... View Article

Which of the following are Indian cattle? (i) Bos indicus (ii) Bos domestica (iii) Bos bubalis (iv) Bos vulgaris (a) (i) and (iii) (b) (i) and (ii) (c) (ii) and (iii) (d) (iii) and (iv)

a) (i) and (iii) Explanation Bos indicus is an Indian cattle and Bos babalis is an Indian cattle but not... View Article

Select the articles from the following list which are biodegradable. (a) Paper (b) Woollen clothes (c) Wood (d) Aluminium can (e) Plastic bag (f) Peels of vegetables

The list of biodegradable articles is mentioned below – (a) paper (b) woolen clothes (c) wood (f) peels of vegetables.... View Article

Which of the following groups contain all synthetic substances? (a) Nylon, Terylene, Wool (b) Cotton, Polycot, Rayon (c) PVC, Polythene, Bakelite (d) Acrylic, Silk, Wool

(c) PVC, Polythene, Bakelite Synthetic materials are made by chemically changing the starting substances to create a material with different... View Article

Given below are statements about the harmful effects of weeds on crop plants. (i) They interfere with harvesting. (ii) They help crop plants to grow healthily. (iii) They compete with crop plants for water, nutrients, space and light. (iv) They affect plant growth. Choose the correct combination of statements. (a) i, iii, iv (b) iii only (c) iii, iv (d) i, ii, iii, iv

(a) i, iii, iv Explanation Harmful effects of weeds on crop of plant are as follows: They interfere in harvesting.... View Article

Given below is a conversation between two farmers Heera and Beera. Heera: Brother Beera, your maize crops looks beautiful! They have grown pretty fast. Beera: Yes, I have sprayed urea this time. What about you? Heera: Well, I am still relying on good old cow dung. I am saving money on buying a tractor. Beera: That’s good. Tractor saves a lot of time and labour. Heera: Yes, it’s been very labour intensive for me and now these weeds have come up. Beera: Try weedicides, they are very effective. Now answer the following questions. a) List the practices which are not environment-friendly and why? b) What is the advantage of modern agriculture implements over traditional ones? c) Name one weedicide and the precaution farmers must take during its application.

a) The use of chemical fertilizers, insecticides, pesticides, weedicides are not environment-friendly as they contain chemicals which are very harmful... View Article

The calorific value of a fuel is expressed in a unit called (a) kilojoule per litre (b) kilogram per millilitre (c) kilojoule per gram (d) kilojoule per kilogram

The calorific value of a fuel is expressed in a unit called kilojoule per kilogram. Calorific value is the amount... View Article

Rohit took with him some nylon ropes when he was going for rock climbing. Can you tell why he selected nylon ropes instead of ropes made of cotton or jute?

Nylon ropes are strong, elastic and lighter as compared to cotton and jute ropes. Advantages and uses of using Nylon... View Article

The process of loosening and turning of soil is called (a) irrigation and manuring (c) tilling and ploughing (b) digging and winnowing (d) harvesting and storage

The process of loosening and turning of soil is called Tilling or ploughing. Before sowing the seeds, it is necessary... View Article

Classify the following diseases as infectious or non-infectious. (a) AIDS (b) Tuberculosis (c) Cholera (d) High blood pressure (e) Heart disease (f) Pneumonia (g) Cancer

(a) AIDS – Infectious (b) Tuberculosis – Infectious (c) Cholera – Infectious (d) High blood pressure – No- Infectious (e)... View Article

Observe the figure given and answer the questions that follow. (a) Label A and B. (b) Identify the process. (c) What happens during this process and what is formed?

(a) A-sperm; B-ovum (egg) Sperm and ovum are the gametes produced by vertebrates. More specifically, sperm is the male gamete... View Article

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