Top 10,10th, Sci.I Return visit..🎷 of Scientific reasons

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*महत्वकांक्षा हा यशाचा मार्ग आहे आणि चिकाटी हे माध्यम आहे.*

*  If a dry handkerchief is dipped in water, it becomes wet immediately, but a wet handkerchief takes time to dry.

* The bread rises during preparation.

*  Eating stale food/ bread can lead to poisoning.

*Distance and displacement are different concepts.

* While working in the rainy season, the farmers keep an iron guard in the open.

* Heart muscles are called involuntary muscles.

* The atomic clock is accurate.

*Food that enters the stomach is acidic.

*. Copper and brass vessels should be polished.

* We can hear the movement of a mosquito's wings, but we cannot hear the movement of our hands.

* Natural gas is an environment-friendly fuel.

*Synthetic detergents are better than soaps.
 * The sky looks blue during the day.

* Oil does not mix with water; But when enough detergent is used, oil and water become one.

* Coal is known as Black Gold.

* Beyond the atmosphere, space appears black.

*Our mass is the same on both the moon and Earth.

* Foods are safe at 5°C.

* A glass bottle full of water should never be kept in the fridge.

*. Static electricity experiments are not successful during monsoons.

*. While buying air-tight food items, check the expiry date on their packaging date.

* Insectivorous plants are attractive in color.

* At present buffet method is used in big functions.

*In the old days, people used to listen to the railway tracks to see when the train would arrive.
No sound is heard in space or on the moon.

* lichen / Dagaḍaphula
(दगडफूल) is an example of symbiotic nutrition.

* Two stainless steel bowls stuck together need to be heated to separate them.

*Amarvel has sucker roots.

* An iron pole feels colder to our hands than a wooden pole on winter nights.

* Soap is not useful in hard water.

* People's lives can be saved from the tsunami disaster.

* Buttermilk is churned to extract butter.

* Paper flakes are attracted to a plastic comb that spins rapidly through the dry hair.

* While fitting the iron run on the wheel, it is heated.

*The sound made when an empty metal vessel is struck with a stick
 * The weight of an object changes from place to place though its mass is constant.
( Definition of mass and weight, inertia, value of g)
Ans:- 
1 Definition- The quantity of matter present in an object or body is called its mass. It is a measure of the inertia of the object.
2. Definition- the gravitational force that acts on the body is called its weight. Weight, W= mg. As the value of the acceleration due to gravity changes from place to place on earth the weight of an object changes from place to place.

* With a specific inertial velocity we can jump higher on the moon than on the Earth.
(Difference in 'g', h=u^2/2g)
Ans:- 
• . There is much more difference between acceleration due to gravity on the moon and the earth.
• . The acceleration due to gravity on the moon (1.63m/s^2) is 1/6 of that on the earth (9.8m/s^2)
• . The formula h=u^2/2g shows that with specific inertial velocity (u). Therefore we can jump higher on the moon than on the Earth.
* Zero group elements / (inert gases)are called noble gases.
(Shell field with an electron, stable electronic configuration)
Ans:-

•  All the electronic shells, including the outermost shell, are completely field, in inert gas.
•  In a chemical reaction, they do not give, accept, or share electrons. Their electronic configuration is stable.
•  At normal temperature they are in a gaseous state hence they are called zero group elements/ noble gas elements/ inert gas elements.

* Elements belonging to the same group have the same valency.
( Same number of Valence electrons, )
Ans:-

•   The number of valence electrons in the outermost shell of an atom indicates its valency.
•  The same number of valence electrons are present in a group. Therefore elements in the same group should have the same valency.
•  Ex. 
• A. Halogens contain 7 electrons in their valence electron therefore their valence is one.
• B. The elements of group 1 contain only one valence electron therefore the elements of group 1 show valency 1.

* Atomic radius goes on increasing down a group.
(Definition, size of atom, new shell) 
Ans:- 

• Definition:- The distance from the center of the nucleus of an atom to the outermost orbital of its electron is called the atomic radius.
• The size of an atom is indicated by its radius.
•  As we go down a group new shell is added. Due to this, the distance between the outermost shell and the nucleus goes on increasing.
•  As the electrons experience from the nucleus the atomic radius goes on increasing down a group.

* It is recommended to use an airtight container for storing oil for a long time.
(Oxidation, rancidity, antioxidants)
Ans:-  

• Edible oil gets oxidized if stored for a long time. Due to the oxidation of oil, it has become rancid, so taste and smell changes.
•  Rancidity is prevented by using antioxidants. Another way of preventing rancidity is storing it in a type container.
• Therefore It is recommended to use an airtight container for storing oil for a long time.

* The gas obtained by heating the limestone becomes milky when passed through fresh lime.
(Chemical reaction, calcium bicarbonate milky)
Answer:-

•   When limestone is heated up to 1000°C it decomposes to calcium oxide and carbon dioxide.
•  If this carbon dioxide is passed in a short time then calcium carbonate is formed due to which it becomes milky. If it is passed a long time through the same solution then calcium bicarbonate is formed due to which the solution becomes colorless.

* Copper or aluminum wires are used for electrical transmission.
(conductivity, resistivity, heat)
Answer:- 

• Copper Cu and aluminum Al are good conductors of electricity.
•  Along with this, the resistance of copper and aluminum is very low, so the heat generated is less. Therefore copper or aluminum wires are used for electrical transmission.

* A household electrical connection requires an earthing wire.
(Defects in equipment, plastic casing, ground voltage)
Ans:- 

•  Due to the defect in the equipment that we are using if a person comes in contact with the metal part of the equipment, severe electric shock can result in death. Because there potential difference of 220 volts between a live wire and a neutral.
•  Also, if the plastic covering of the wire is removed by weathering, a large amount of current starts flowing through it and it generates a lot of heat.
•  But if the earthing wire is connected to the ground, current flows to the ground having zero potential, avoiding the above accident.
• Therefore A household electrical connection requires an earthing wire.

 

* Fish can survive even in frozen ponds in cold regions.
(Anomalous behavior of water, density of ice)
Ans:- 

•  In cold regions, the temperature of the atmosphere falls below 0°C in winter, resulting in the freezing of lakes.
•  When the temperature of the surface water of the lake reaches 4°C, the volume of the water decreases and it sinks to the bottom. This process continues until all the water in the pond reaches 4°C.
•  when the temperature of the surface water drops to 0°C a layer of ice forms on the surface of the water. Since ice is a poor conductor of heat, water under the ice stays at 4°C. Fish can easily survive in this 4°C water.

* Low melting point material wire is used to make molten fuse wire.
(Restricts high voltage current, series connection)
Ans:- 

• Fused wires add a common connection to the circuit to prevent damage to the equipment and the circuit, due to excessive current flowing through the electrical equipment.
•  If the increased current in the circuit passes through the circuit, the temperature of the wire increases, thus breaking the fuse wire.
• Therefore Low melting point material wire is used to make molten fuse wire.

* Appliances like electric irons and toasters use alloys of nichrome instead of pure metal.
(Principles - Thermal Effects, Resistivity, Oxidation)
Answer:- 

•  The working of appliances like electric iron, and toasters depends on the thermal effect of electric current.
•  Nichrome [Ni+Cr+(Fe)] alloy has very high resistivity. (66 times that of copper). Nicron can be heated to high temperatures without oxidizing. However, this cannot be done in the case of pure metals.
• Therefore Appliances electric irons and toasters use alloys of nichrome instead of pure metal.