A person who is habituated to a drug due to its prolonged use is called drug addict. This is called drug addiction or drug abuse.

Scratch is a software used to create animations, cartoons and games easily.

(i) LINUX

(ii) WINDOWS

(i) The cancerous cells migrate to distant parts of the body and affect new tissues.

(ii) This process is called metastasis.

An amalgam is an alloy of mercury with another metal

(i) Household utensils

(ii) Electrical cable industry

(iii) Aeroplanes and other industrial parts

On heating at 800°C, aluminium burns very brightly forming it's oxide and nitride

\(\begin{aligned} & 4 \mathrm{Al}+3 \mathrm{O}_2 \rightarrow 2 \mathrm{Al}_2 \mathrm{O}_3 \text { (Aluminium oxide) } \\ & 2 \mathrm{Al}+\mathrm{N}_2 \rightarrow 2 \mathrm{AlN} \text { (Aluminium nitride) } \end{aligned}\)

Lead.

Uranium.

Script editor is where you edit your programs or your sprite's pictures.

The script editor has three main parts:

(i) Script area: Where you build scripts.
(ii) Block menu: Where you choose the category of blocks (programming statements) to use.

(iii) Block palette: Where you choose the block to use.

Regular physical exercise can give the following benefits.

(i) It helps to burn calories and brings about weight loss. Obesity can be avoided by exercising regularly.

(ii) It brings about changes in the brain which can reduce stress and anxiety due to production of certain hormones.

(iii) It increases energy levels in the body.

(iv) It is good for the muscles and bones.

(v) It brings in a lot of positive thoughts and helps fight depression.

(vi) It can reduce risk of chronic diseases.

Diet Management:

(i) Reduction in the intake of calories, low saturated fat and cholesterol rich food, low carbohydrates and common salt are some of the dietary modifications.

(ii) Dietrich in polyunsaturated fatty acids (PUFA) is essential.

(iii) Increase in the intake of fibre diet, fruits and vegetables, protein, minerals and vitamins are required.

Physical activity: Regular exercise, walking and yoga are essential for body weight maintenance

Addictive substance avoidance : Alcohol consumption and smoking are to be avoided.

(i) Stage is the background appearing when we open the scratch window.

(ii) The background will most often be white. We can change the background colour as we like.

Bessemerisation:

(i) The molten matte is transferred to Bessemer converter in order to obtain blister copper.

(ii) Ferrous sulphide from matte is oxidized to ferrous oxide, which is removed as slag using silica.

\(\begin{aligned} & 2 \mathrm{FeS}+3 \mathrm{O}_2 \longrightarrow 2 \mathrm{FeO}+2 \mathrm{SO}_2 \uparrow \\ & \mathrm{FeO}+\mathrm{SiO}_2 \longrightarrow \underset{\text { (Iron silicate) }}{\mathrm{FeSiO}_3 \text { (slag) }} \end{aligned}\)

\(\begin{aligned} & 2 \mathrm{Cu}_2 \mathrm{~S}+3 \mathrm{O}_2 \longrightarrow 2 \mathrm{Cu}_2 \mathrm{O}+2 \mathrm{SO}_2 \uparrow \\ & 2 \mathrm{Cu}_2 \mathrm{O}+\mathrm{Cu}_2 \mathrm{~S} \longrightarrow \\ & 6 \mathrm{Cu}+\mathrm{SO}_2 \uparrow \\ & (\text { Blister copper }) \end{aligned}\)

(i) ₈₈X²²⁶ ------>₈₆Y²²² + ₂He⁴ + energy

Mass Number = 222

Atomic Number = 86

(ii) Mass defect in the reaction (m) = 1 kg

Velocity of light (c) = 3 x 10⁸ ms^-1

By Einstein's equation,

Energy released E = mc²

So E = 1 x (3 x 10⁸)²

= 0.9 x 10¹⁷ J

When iron is exposed to moist air, it forms a layer of brown hydrated ferric oxide on its surface. This compound is known as rust and the phenomenon of formation of rust is known as rusting

\(4 \mathrm{Fe}+3 \mathrm{O}_2+\mathrm{xH}_2 \mathrm{O} \longrightarrow 2 \mathrm{Fe}_2 \mathrm{O}_3 \cdot \mathrm{xH}_2 \mathrm{O} \text { (rust) }\)

Soddy and Fajan's displacement laws :

(i) When a radioactive element emits an alpha particle, a daughter nucleus is formed whose mass number is less by 4 units and the atomic number is less by 2 units, than the mass number and atomic number of the parent nucleus.

(ii) When a radioactive element emits a beta particle, a daughter nucleus is formed whose mass number is the same and the atomic number is more by 1 unit, than the atomic number of the parent nucleus.

Hint: Other name is "Radioactive displacement law".

(i) Scratch is a software used to create animations cartoons and games easily.

(ii) Scratch is a Visual Programming Language.

(iii) It was developed in the Massachusetts Institute of Technology (MIT) Media Lab to make programming easier and more fun to learn.

Scratch Environment Editor :

(iv) The Scratch editor has three main parts: They are Stage, Sprite and Script editor.

(v) Stage: Stage is the background appearing when we open the scratch window. The background will most often be white. You can change the
background colour as you like.

(vi) Sprite:

◆ The characters on the background of a Scratch window are known as Sprite.

◆ Usually a cat appears as a sprite when the Scratch window is opened. The software provides facilities to make alterations in sprite.

(vii) Script editor/ Costume editor: Where you edit your programs or your sprites pictures.

The script editor has three main parts :

(i) Script area: Where you build scripts.

(ii) Block menu: Where you choose the category of blocks (programming statements) to use.

(iii) Block palette: Where you choose the block to use.

(i) Education and counselling: Education and proper counselling will help the alcoholics to overcome their problems and stress, to accept failures in their life.

(ii) Physical activity: Individuals undergoing rehabilitation should be channelized into healthy activities like reading, music, sports, yoga and meditation.

(iii) Seeking help from parents and peer groups: When a problematic situation occurs, the affected individuals should seek help and guidance from parents and peers. This would help them to share their feeling of anxiety, wrong doing and get rid of the habit.

(iv) Medical assistance: Individual should seek help from psychologists and psychiatrists to get relieved from this condition and to lead a relaxed and peaceful life.

(v) Alcohol de-addiction and rehabilitation programmes are helpful to the individual so that they could get rid of the problem completely and can lead a normal and healthy life.

Methods of preventing corrosion :

Alloying:

(i) The metals can be alloyed to prevent from the process of corrosion

(ii) E.g: Stainless Steel

Surface Coating: It involves application of a protective coating over the metal. It is of the following types

(a) Galvanization: It is the process of coating zincon iron sheets by using electric current

(b) Electroplating: It is a method of coating one metal over another metal by passing electric current

(c) Anodizing:

(i) It is an electrochemical process.

(ii) It converts the metal surface into a decorative,durable and corrosion resistant.

(ii) Aluminium is widely used for anodizing Process

(d) Cathodic Protection:

(i) It is the method of controlling corrosion of a metal surface protected is coated with the metal which is easily corrodible.

(ii) The easily corrodible metal is called Sacrificial metal to act as anode ensuring cathodic protection.

Smelting (in a Blast Furnace):

(i) The charge consisting of roasted ore, coke and limestone in the ratio 8:4:1

(ii) Smelted in a blast furnace by introducing it through the hopper arrangement at the top.
(iii) There are three important regions in the furnace

a) The Lower Region (Combustion Zone):

(i) The temperature is at 1500°C.
(ii) Hot gases Coke burns with oxygen to form CO₂ when the charge comes in contact with a hot blast of air.

\(\mathrm{C}+\mathrm{O}_2 \xrightarrow[\Delta]{1500^{\circ} \mathrm{C}} \mathrm{CO}_2+\text { Heat }\)

It is an exothermic reaction since heat is liberated

(b) The Middle Region (Fusion Zone):

(i) The temperature prevails at 1000°C.

(ii) CO₂ is reduced to CO

\(\mathrm{CO}_2+\mathrm{C} \xrightarrow[\Delta]{1000^{\circ} \mathrm{C}} 2 \mathrm{CO}+\text { Heat }\)

Limestone decomposes to calcium oxide and CO₂

\(\mathrm{CaCO}_3 \xrightarrow[\Delta]{1000^{\circ} \mathrm{C}} \mathrm{CaO}+\mathrm{CO}_2-\text { Heat }\)

(iii) These two reactions are endothermic due to absorption of heat.

(iv) Calcium oxide combines with silica to form calcium silicate slag.

\(\mathrm{CaO}+\mathrm{SiO}_2 \longrightarrow \mathrm{CaSiO}_3\)

(c) The Upper Region (Reduction Zone):

(i) The temperature prevails at 400°C.

(ii) Carbon monoxide reduces ferric oxide to form a fairly pure spongy iron.

\(\mathrm{Fe}_2 \mathrm{O}_3+3 \mathrm{CO} \xrightarrow{400^{\circ} \mathrm{C}} 2 \mathrm{Fe}+3 \mathrm{CO}_2 \uparrow\)

The molten iron is collected at the bottom of the furnace after removing the slag.

(iii) The iron thus formed is called pig iron.
(iv) It's remelted and cast into different moulds. This iron is called cast iron.

Nuclear reactor: A nuclear reactor is a device in which the nuclear fission reaction takes place in a self - sustained and controlled manner to produce electricity.

Essential parts and their functions:

Fuel:

(i) A fissile material is used as the fuel.

(ii) The commonly used fuel material is uranium.

Moderator :

(i) It is used to slow down the high energy neutrons to provide slow neutrons.

(ii) Graphite and heavy water are the commonly used moderators.

Control rod:

(i) It is used to control the number of neutrons in order to have sustained chain reaction.

(ii) Mostly boron or cadmium rods are used as control rods.

Coolant:

(i) It is used to remove the heat produced in the reactor core to produce steam.

(ii) This steam is used to run a turbine in order to produce electricity. Water, air and helium are some of the coolant materials.

Protection wall : A thick concrete lead wall is built around the nuclear reactor in order to prevent the harmful radiations from escaping into the environment.