Explain any one method of crop production which ensures high yield.
One of the methods of crop production that ensures high yield is crop rotation. This method involves growing two or more varieties of crop in the same fertile land in a sequential and seasonal order in a definite pattern. A crop utilises some particular nutrients in larger quantities from the soil and thus the soil gets enriched in this process. Therefore, crops having different nutrient requirements are rotated. For example, legumes which have nitrogen-fixing bacteria in their root nodules supply the soil with nitrogen.
How do you differentiate between capture fishing, mariculture and aquaculture?
How do good animal husbandry practices benefit farmers?
What are the desirable characters of bee varieties suitable for honey production?
How do plants get nutrients?
How are fish obtained?
What is genetic manipulation? How is it useful in agricultural practices?
What are the desirable agronomic characteristics for crop improvements?
What factors may be responsible for losses of grains during storage?
Which method is commonly used for improving cattle breeds and why?
How do biotic and abiotic factors affect crop production?
Which of the following has more inertia: (a) a rubber ball and a stone of the same size? (b) a bicycle and a train? (c) a five-rupees coin and a one-rupee coin?
State the universal law of gravitation.
Which of the following are matter?
Chair, air, love, smell, hate, almonds, thought, cold, cold-drink, smell of perfume.
A force of 7 N acts on an object. The displacement is, say 8 m, in the direction of the force (Fig. 11.3). Let us take it that the force acts on the object through the displacement. What is the work done in this case?
What is meant by a pure substance?
How does the sound produced by a vibrating object in a medium reach your ear?
In a reaction, 5.3 g of sodium carbonate reacted with 6 g of ethanoic acid. The products were 2.2 g of carbon dioxide, 0.9 g water and 8.2 g of sodium observations are in agreement with the law of conservation of mass.
sodium carbonate + ethanoic acid → sodium ethanoate + carbon dioxide + water
What are canal rays?
State any two conditions essential for good health.
How is our atmosphere different from the atmospheres on Venus and Mars?
Write the distribution of electrons in carbon and sodium atoms.
A lamp consumes 1000 J of electrical energy in 10 s. What is its power?
What is power?
A battery lights a bulb. Describe the energy changes involved in the process.
Abdul, while driving to school, computes the average speed for his trip to be 20 km h-1. On his return trip along the same route, there is less traffic and the average speed is 40 km h-1. What is the average speed for Abdul’s trip?
A bullet of mass 10 g travelling horizontally with a velocity of 150 m s-1 strikes a stationary wooden block and comes to rest in 0.03 s. Calculate the distance of penetration of the bullet into the block. Also calculate the magnitude of the force exerted by the wooden block on the bullet.
For the symbol H,D and T tabulate three sub-atomic particles found in each of them.
Differentiate between parenchyma, collenchyma and sclerenchyma on the basis of their cell wall.
Fill in the gaps in the following table illustrating differences between prokaryotic and eukaryotic cells.
Prokaryotic Cell | Eukaryotic Cell |
1. Size : generally small (1-10 μm) 1 μm = 10-6 m |
1. Size generally large (5-100 μm) |
2. Nuclear region: ________________ and known as _________________ |
2. Nuclear region: well defined andsurrounded by a nuclear membrane |
3. Chromosome: single |
3. More than one chromosome |
4. Membrane-bound cell organelles absent | 4. _______________________ _______________________ |
Composition of the nuclei of two atomic species X and Y are given as under
X Y
Protons = 6 6
Neutrons = 6 8
Give the mass numbers of X and Y. What is the relation between the two species?