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CBSE Class 10 Science Previous Year Question Paper with Solution (2012) - Free PDF Download
Previous Year Science Question Paper for CBSE Class 10 - 2012
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1. According to CBSE Class 10 Science book, why does our tooth decay when the pH of the mouth goes below 5.5?
When we eat something sweet that contains sugar, some sugar does remain in our mouths. When the already existing bacteria in the mouth break down the sugar, acids are formed. This formed acid lowers the pH of the mouth. When the pH of the mouth moves to the acidic side, teeth start to decay. One has to make sure they clean their mouths properly after eating something, especially after eating something sweet. You should brush your teeth twice a day to keep them bacteria-free.
2. According to CBSE Class 10 Science book, how does chemical coordination take place in animals and humans?
In animals and humans, chemical coordination takes place with the help of hormones. Hormones are chemicals that help the body’s functions. Various glands in the body secrete hormones from time to time. Endocrine glands and the Exocrine glands are two types of glands that secrete various chemicals into the body. The exocrine glands release their chemicals in the ducts, these chemicals help in the digestion of food. The endocrine glands release hormones that help the body perform certain functions. For instance, the pituitary gland secretes growth hormone that helps the body grow.
3. What is covered in Chapter 4 of NCERT Class 10 Science book?
Chapter 4 of NCERT class 10 Science book is on Carbon and its compounds. The chapter talks about carbon as an element. The atomic number and atomic mass of Carbon. The role of carbon in organic chemistry is also elaborated in the chapter. The allotropes of carbon, their structures, and their uses are also covered. The various compounds that are formed with the help of carbon are also elaborated upon. The chemical and physical properties of carbon-containing compounds are given. The methods of preparing carbon-containing compounds are also given.
4. According to the CBSE Class 10 Science book, what are the ways we can harness the energy of the ocean?
Energy is an untouched source of energy. There are two major ways we can use the energy of the ocean. One is Tidal energy and the other is Ocean Thermal Energy Conversion. Wave energy is converted to electricity in various ways. This includes installing oscillating water columns, oscillating bodies, and overtopping converters. Tidal energies can be harnessed with the help of tidal turbines and tidal barrages. There are multiple advantages to using the energy from the ocean. Energy is low cost, renewable, abundant, and clean.
5. According to CBSE Class 10 Science book, why do veins have thinner walls than arteries?
Arteries carry blood from the heart to the body, as the heart pumps out the blood at full pressure, the walls of the arteries are thick and elastic. Veins carry blood from the body into the heart, this blood travels around in the body with less pressure. The layers of the arteries and veins are the same, made up of smooth muscle tissues, but the veins just have a lesser amount of the layers. As the pressure of the blood in veins is low, its walls are comparatively thinner. The diameter of veins is larger than that of the arteries. Veins are larger as they store more amount of blood.
You can find answers to many more such questions from the question paper of previous years for class 10 Science in the website of Vedantu. Visit us here.
