Class 11 Hardware Concepts, Informatics Practices (IP) - CBSE Notes | CBSE Guide

Class 11, Hardware Concepts - CBSE Informatics Practices (IP) Guide

Computer is an electronic device which can take data as input, process it, and gives out the information as output.
Terminologies used in Computers
Data: Collection of raw facts and figures is called Data.
Input: The data which is given to a computer.
Process: Work done by the computer according to instruction given.
Information: The processed data is called as Information. It is meaningful.
Output: The information which is given by the computer is called as Output.
Hardware: The physical components or parts of a computer.
Software: A set of programmes are called as a Software.
I-P-O Cycle: The first stage is called as Input stage. The second stage is called as Process stage. The third stage is called as Output stage. After getting output again it can be used as Input, then again after process, we get the Output. The whole process can be rotated like a cycle which is called as Input-Process-Output cycle (I-P-O).
Block Diagram or Basic Structure of a Computer: - Block Diagram or image of Basic Structure of a Computer
(CPU - Central Processing Unit; MU - Memory Unit; ALU - Arithmetic Logic Unit; CU - Control Unit)
Classification of Computers
CBSE Guide NCERT Solution - Types of Computers chart

Input Unit or Input Devices: The devices which are used to supply the data to the computer are called Input Devices. Examples: keyboard, mouse, joystick, OMR, OR etc.
Key Board: It is one of the most important input devices which are used for typing, giving instructions and many other purposes. Key Boards are available in various formats.

Mouse: Also known as Graphical Input Device. It is a painting device. Mouse is used to used draw diagrams, selecting menus and also to perform other tasks mostly in combination with keyboard &/or Monitor. There are three types of Mouses: (1) Mechanical Mouse (2) Optical Mouse (3) Wireless Mouse.
Light Pen: A pointing device consisting of a photocell mounted in a per-shaped tube. A light pen is a light-sensitive computer input device, basically a stylus that is used in conjunction with a computer's CRT display. It allows the user in a similar way to a touch-screen but with greater positional accuracy to select text, draw pictures and interact with user interface elements on a computer screen or monitor.  
Central Processing Unit (CPU): It is used to perform arithmetic (+, -, ×, /, *) and logical operations such as (>, <, =, <=, =>, <>).
Control Unit (CU): This unit controls the flow of data from input devices to memory and from memory to input devices.
Memory Unit (MU): It is used to store and read data. The data will be stored in small location which are called Memory Cells. It stores data in the form of 0, 1 which is called as bits (Binary Digits). A group of 8 bits is called a byte. One Byte can be used to represent a data term or character. The other units of memory are -
1024 Bytes = 1 Kilo Byte (1 KB)
1024 KB = 1 Mega Byte (1MB)
1024 MB = 1 Giga Byte (1 GB)
1024 GB = 1 Tetra Byte (1 TB)
 There are two types of memory units - 1. Main or Primary Memory, 2. Secondary Memory.
Main Memory or Primary Memory: This type of memory is used to store programs and data which run the computer. Examples of Primary Memory Units are - RAM (Random Access Memory), ROM  (Read Only Memory).
RAM: This memory is responsible for read, write and erase the programs or data in the memory. It is also called volatile memory since this memory is temporary only.
ROM: As its name Read Only Memory denotes this memory is used for read only purpose. We cannot write or erase the programs in ROM. That is why this is called permanent or non-volatile memory.
Firmware: The pre-written program which is permanently stored in ROM is called Firmware.
Secondary Memory Devices: Since the primary memory has a limited storage capacity and is not permanent, the secondary storage devices are used to store large amount of data permanently. The following are the various examples -
(1) Magnetic Media Storage Devices: Magnetic Tapes, Floppy Disk, Hard Disk, Zip Drive.
(2) Optical Storage Devices: CD ROM, DVD.
(3) Flash Drive or USB Drives or Jump Drive: Flash drives, also known as USB drives or jump drives, contain mini circuit boards with memory chips to save and retain your data and information. There are no moving parts, and separate media is not necessary to read or record data. This type of storage media is called solid state memory, and differs from optical and magnetic drives. Example: Pen Drive, SD Cards.

Floppy Disks: It is one of the oldest types of portable storage device used to store small amount of data. A floppy disk stores data in the Tracks and Sectors. The first 8-inch floppy disk had a storage capacity of about 80 KB. By 1986, IBM introduced the 3-1/2 inch floppy disk with 1.44 MB of storage space. 
Advantages: (a) Portable, (b) Inexpensive, (c) Reusable.
Disadvantages: (a) Small storage capacity, (b) Delicate, (c) Slow to access and retrieve data, (d) Often data is lost because of weak structure of the disk.
Hard Disks: It is used to store large volume of data. It contains more than one disk arranged on a single spindle. Now-a-days hard disks of huge data storage capacity equivalent to 1 Trillion GB are being used.
Advantages: (a) Large storage capacity (b) Can store and retrieve data in seconds, (c) More reliable and permanent storage.
Disadvantages: (a) It needs to be fixed inside CPU; (b) It is slower than RAM/ROM
Compact Disk (CD): It is a low-cost optical media or optical storage device. A blank, standard CD has a diameter of 120 mm, and can hold up to 700 MB of digital data equivalent of approximately 80 minutes of audio. There are three types of CDs: (1) CD-ROM (Compact Disk - Read Only Memory, (2) CD-R (Compact Disk - Recordable), (3) CD-RW (Compact Disk - Rewritable). The 120 mm disc has a storage capacity of 74 minutes of audio or 650 MB data. CD-R/RWs are available with capacities of 80 minutes of audio or 700 MB.
DVD (Digital Versatile Disk): DVD is a digital optical disc storage format that looks same as Compact Disk and is used to store high capacity data like high quality videos and movies. It is also used to store operating system. It is invented and developed by 4 companies named Philips, Sony, Toshiba and Panasonic in 1995. DVD is able store about 15 times as much information (data) and also 20 times faster than CD. A DVD is a Super Destiny Disk (SD).
DVD storage capacity
Disc type
Data capacity
DVD-quality video (hrs)
Single-layer, single-sided
Single-layer, double-sided
Dual-layer; single-sided
Dual-layer, double-sided

Pen Drive (PD): Pen Drive also referred as USB flash drive is a portable device which allows user to transfer data (text, images, videos etc) to and from computer quickly. Users can easily read and write the data on the Pen Drive by plugging it into the USB port on the computer. The first USB flash drive appeared on the market in late 2000, providing a storage capacity of 8 MB.  The world's new largest flash drive is the 2TB Kingston Data Traveler Ultimate GT.
OMR (Optical Mark Reader): Optical Mark Recognition (also called Optical Mark Reader and OMR) is the process of capturing human-marked data from document forms such as surveys and tests. Optical Mark Readers are input devices which are used to read questionnaires, multiple choice examination papers in the form of lines or shaded areas.
OCR (Optical Character Reader): OCR (Optical Character Recognition) recognizes all the characters from the paper document, collects and stores them into editable document. This device not only scans the marks but also scans each character. The difference between OMR and OCR is that OMR can read the marks filled in circles but it can't recognize the characters.
MICR (Magnetic Ink Character Reader): MICR devices are used to read recognize the characters which are printed with special ink called as Magnetic Ink Characters. It is mainly used in Banks to find the Duplicate cheques or DD and in Post Offices to find duplicate IPO. 
Scanner: Scanner is an input device. It is similar to a photo copier which creates an electronic form of a printed image into a computer. There are three types of scanners: (1) Hand-held Scanner (2) Flat-bed Scanner (3) Drum Scanner
Barcode Reader: It is one of the most widely used input devices now-a-days. A barcode (also bar code) is an optical, machine-readable, representation of data; the data usually describes something about the object that carries the barcode. Traditional barcodes systematically represent data by varying the widths and spacing of parallel lines printed on the product’s label.
Biometric Sensors: It is an input device used for identifying Human features such as DNA identification, Face shape recognition, Voice & Fingerprint identification.
Output Unit or Output Devices: The devices which are used to take the output given by the computer are called as Output Devices. Example: Monitors, Printers, Plotters, Speakers.
Monitor: It is the most commonly used output device in computers. It is used to display the information or data on the screens. A character / image is formed by grouping tiny dots called as pixel (picture elements). There are various kinds of monitors like: Cathode Ray Tube (CRT), Liquid Crystal Display (LCD), Thin Film Transistor (TFT).
Impact Printers: It is an output device used for creating paper copies from the computer. Impact printer refers to a class of printers that work by banging a head or needle against an ink ribbon to make a mark on the paper. This includes dot-matrix printers, daisy-wheel printers, and line printers.
Non-Impact Printers: In these printers there is no mechanical contact between the print head and the paper. These printers print without banging a ribbon onto paper. Non-impact printers do not use a striking device to produce characters on the paper; and since these printers do not hammer against the paper they are much quieter than impact printers. Laser, LED, inkjet, solid ink, thermal wax transfer and dye sublimation printers are examples of non-impact printers.

Class 11 Informatics Practices (IP) - Hardware Concepts  Guess Questions

1.       What is a computer?
2.       What do you understand by I-P-O Cycle?
3.       What are the functional parts of a computer?
4.       What are the components of a CPU?
5.       What is the function of ALU?
6.       What role does the input unit play in computer?
7.       What is the difference between Internal and External Memories?
8.       What do you mean by the terms Hardware, Software, Firmware?
9.       What is the difference between RAM and ROM?
10.    Give examples of Non-Impact printers.
11.    How are the computers classified (type of computers)?
12.    What is scanner? Is scanner output or input device?
13.    What is OMR? What is the difference between OMR and OCR?
14.    Make a sketch of the basic structure of a computer.

10 CBSE Guide for History - Events and Processes - Nationalism in India | Additional Questions Answers and More

Class 10, Events and Processes: Nationalism in India

Unit III, NCERT History India and the Contemporary World II

CBSE Guide n Guess - Additional Sample Questions - graphic for Class 10 History
Question.1: What was the plan of Gandhiji to launch Non-Cooperation Movement ?
How did Non-Cooperation became a mass movement ?
Answer: Non-Cooperation took a shape of mass-movement after Gandhiji proposed that:
1. Non-Cooperation Movement should unfold in stages.
2. First of all, titles awarded by the government should be surrendered.
3. Secondly, Indians should boycott civil services, army, police, court, legislative councils, government schools and foreign goods.
4. In case government used repression, a full Civil Disobedience Movement should be launched.   

Question.2: What were the initial satyagraha movements led by Gandhi ?
What did Gandhiji do immediately after his arrival to India ?
Answer: Mahatma Gandhi after his arrival in India, organized three small but important satyagraha movements which were –
(a) In 1916, Gandhiji organized Champaran satyagraha movement in Bihar. This movement was against oppressive plantation system.   
(b) In 1917, he organized satyagraha movement in support of poor peasants of Kheda district in Gujarat.
(c) In 1918, Gandhiji went to Ahmedabad to organize a satyagraha movement amongst cotton mill workers. 

Question.3: Write a short note on ‘Rowlatt Act’.
Answer: In 1919, the Imperial Legislative Council passed the Rowlatt Acts, giving the Indian colonial authorities enormous powers to repress the political activities and satyagrahis. It also allowed detention of political prisoners without trials for two years. This Act was hurriedly passed by the British Parliament despite there was a united opposition from all Indian members.
A demonstration against Rowlatt Acts resulted in a massacre of unarmed Indian protesters Indian protesters at Amritsar (Jallianwala Bagh) by the British soldiers. This incident left permanent scar on Indo - British relations and was the prelude to Mahatma Gandhi’s organized campaign of Non-Cooperation Movement against the British Government.    

Question.4: Write a short note on ‘Khilafat Movement’.
Who started Khilafat Movement ? What were the aims of Khilafat Movement ? How did this movement help in     bringing unity between Hindus and Muslims of this country ?
Answer: The movement arose in India in early 20th century as a result of Muslim fears for the integrity of Islam. These fears were aroused by Italian and Balkan attacks on Ottoman Empire of Turkey whose sultan - the Khalifa was the spiritual head of the Islamic world. There were rumours after the defeat of Turkey in World War I that a harsh peace treaty was going to be imposed on Ottoman Turkey. A movement in defence of Khalifa’s temporal powers was launched in India led by the Ali brothers – Muhammad Ali and Shaukat Ali with Abul Kalam Azad. A Khilafat Committee was formed in Bombay in March 1919. These leaders joined forces with Mahatma Gandhi’s Non-Cooperation movement for Indian freedom, promising non-violence in return for his support of Khilafat Movement.
Gandhiji saw this as an opportunity to bring Muslims under the umbrella of a unified National Movement. He tried hard to achieve Hindu-Muslim unity by supporting the Khilafat Movement. The Khilafat Movement coincided with the inception of Satyagraha, thus giving the illusion of a unified Non-Cooperation Movement against British in support of Khilafat as well as Swaraj.       
Question.5: What happened in India during 1918 - 1921 which cost millions of life ?
Answer: During this period, crops failed in many parts of India resulting in acute shortage of foods. This was followed by an epidemic. About 12 - 13 million people died as a result of famines and the epidemic.   

Question.6: Which tax was introduced during the First World War ? How was the War cost met ?
Answer: Income tax was introduced during the First World War in Britain.
To meet war cost, custom duties were increased. 


Acids, Bases and Salts - Class 7 Science Chapter 5, NCERT Solutions and Notes

Class 7 Science Chapter 5 - Acids, Bases and Salts

NCERT Solutions - NCERT Answers - NCERT Notes
Important Terms (Definitions)  
Metals: Metals are generally lustrous solids, malleable, ductile and good conductors of heat and electricity.
Non-metals: Non-metals are generally non lustrous brittle and poor conductor of heat and electricity.
Acids: These are the compounds formed by the reaction of acidic oxide with water and have sour taste.
Mineral Acids: Acids which are capable of forming hydrogen ions when dissolved in water are mineral acids. Such types of acids are also called inorganic acidsmfor example, HCL H2SO4 HNO3 etc.
Strong Acids: These are the acids which are almost completely ionized in aqueous solution. Examples of strong acids - HCL, HNO3, H2SO4.
Weak Acids: Acids which are weakly ionized are called weak acids. For example CH3COOH, (COOH)2
Base: Substances whose molecules have hydroxide (OH-) ions which are set free in aqueous solution are termed as 'Base'. In short a 'Base' is a substance that contains hydroxyl group.
Dilute Acid: A dilute acid is one which contains only a small proportion of solute.
Concentrated Acid: A concentrated acid solution is one which contains high proportion of solute.
Salt: The product formed due to the reaction between an acid and a base.
Alkalies (Alkali): The Hydroxides of metals, which dissolve in water, are known as alkalies.
Indicator: The substances which give different colours with acid and base are called indicators. For example - Litmus, Methyl oranges, Phenolphthalein.
Corrosion: The process that takes place when metals and alloys that undergoes chemical reaction because of the presence of oxygen, water or acid in their immediate environment is known as corrosion. Corrosion is a slow process.
Neutralisation: It's a term for the chemical reaction that takes place between acid and base to form salt and water.
Strong Base: A base which is almost completely ionized in aqueous solution is called a strong base. For example: NaOH, KOH.
Weak Base: Those bases which are weakly or partially ionized are termed as weak bases. For example: Baking soda solution, NH4OH.
Water of Crystallisation: The crystals of some salts contain some water molecules associated with them. These water molecules are known as 'Water of Crystallisation'.
Slaked Lime: Slaked Lime is the other name of calcium hydroxide, Ca(OH)2. Calcium oxide is considered a strong base, because it is gets ionized almost completely.
Neutral Salt: The salt formed when a strong acid is neutralised by a strong base, is called Neutral Salt.
Deliquescent: Some salts have tendency to absorb water from atmosphere (air) and thereby change into a solution. Such substances are called deliquescent. image
Following are the answers of Class 7 Science NCERT Textbook Exercise Questions. For extra or additional important questions answers please refer to our CBSE Guide (CBSE Notes)  
Question 1: State the differences between acids and bases.
1. Acids are sour to taste.
2. Acids turn blue litmus red.
3. Acids contain hydrogen ion.
1. Bases are bitter to taste.
2. They turn red litmus blue.
3. They contain hydroxyl ion.

Question 2: Ammonia is found in many household products, such as window cleaners. It turns red litmus blue. What is nature?
Answer: The nature of ammonia is basic.
Question 3: Name the source from which litmus solution is obtained. What is the use of this solution?
Answer: Litmus solution is obtained from lichens. Litmus solution is prepared by dissolving a natural dye which is extracted from lichens into distilled water.
It is used as an indicator to distinguish between acids and bases.
Question 4: Is the distilled water acidic / basic / neutral? How would you verify it?
Answer: Distilled water is neutral. This can be verified through litmus test as it will not change the colour of the litmus paper.
Question 5: Describe the process of neutralisation with the help of an example.
Answer: Neutralisation is the term used for the reaction between an acid and a base to form salt and water. It is an exothermic reaction where heat is evolved.
An ideal example of neutralisation is - taking antacids like Milk of Magnesia or Magnesium Hydroxide, Baking Soda (Sodium Bicarbonate) etc. which contains a base are used for reducing the acidity in stomach. It reduces acidity through neutralisation when excess acid present in the stomach gets neutralised.     
Question 6: Mark "T" if the statement is true and "F" if it's false.
(a) Nitric acid turns red litmus blue.
(b) Sodium hydroxide turns blue litmus red.
(c) Sodium hydroxide and Hydrochloric acid neutralise each other and form salt and water. 
(d) Indicator is a substance which shows different colours in acidic and basic solutions.
(e) Tooth decay is caused by the presence of a base.
Answer: (a)F. (b)F. (c)T. (d)T. (e)F.  
Question 7: Dorji has a few bottles of soft drink in his restaurant. But, unfortunately, these are not labelled. He has to serve the drinks on the demand of customers. One customer wants acidic drink, another wants basic and third one wants neutral drink. How will Dorji decide which drink is to be served to whom?
Answer: Dorji can decide his drinks with the help of litmus paper:
a. the drink which will turn a red litmus paper blue would be basic.
b. the drink which will turn a blue litmus paper red would be basic and,  
c. the drink which remains unaffected by either red or blue litmus is neutral.
Question 8: Explain why -
(a) An Antacid tablet is taken when you suffer from acidity.
(b) Calamine solution is applied on the skin when an ant bites.
(c) Factory waste is neutralised before disposing it into the water bodies.
(a) Antacid tablets like Magnesium Hydroxide which contains a base are taken for reducing the acidity in stomach. It reduces acidity problems by neutralising the excess acid present in the stomach.
(b) When ant bites it injects an acidic liquid (formic acid) into the skin. This acid causes inflammation to the skin. The effect of the sting can be reduced or neutralised by applying calamine solution to that place. This happens because of the neutralisation reaction as calamine contains zinc carbonate which is a weak base and causes no harm to the skin.
(c) Factory wastes mostly contain acids. If these are allowed to go direct into the water bodies, the acids will kill the fish and other living things present in the water. Hence, factory waste is neutralised before disposing it into threw water bodies.        
Question 9: Three liquids are given to you. One is hydrochloric acid, another is sodium hydroxide and third is sugar solution. How will you identify them? You have only turmeric indicator.
Effect on turmeric indicator
1. Hydrochloric Acid
2. Sodium Hydroxide
3. Sugar solution
Yellow to blue
Yellow to red
No change

Question 10: Blue litmus paper is dipped in a solution. It remains blue. What is the n nature of the solution? Explain.
Answer: As the colour of the blue litmus paper remains unaffected hence, the solution must be basic.   
Question 11: Consider the following statements and tell which of these statements are correct -
(a) Both acids and bases change colour of all indicators.
(b) If an indicator gives a colour change with an acid, it does not give a change with a base.
(c) If an indicator changes colour with a base, it does not change change colour with an acid.
(d) Change of colour in an acid and a base depends on the type of the indicator.
Answer: (a) and (d) are true.
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