Current Affairs 2nd Class

        Logical Functions         A computer is very smart and apart from performing   mathematical calculations, it can also give some additional information based on some decisions for example, if you got 40 marks in your test and your friend got 35, we can say that you performed I better than your friend because 40 is greater than 35. In the same way, computers use logical Potions to provide basic comparison and return True or FALSE value based on the evaluation and the instructions given. Logical function means applying logic to the result obtained after completing mathematical calculations. Therefore, a decision is taken according to the given commands.              Suppose total Marks = 325 (mathematical calculations) If total Marks > 200; (decision) PRINT 'Pass'. (Command) If total Marks < 200; (decision) PRINT 'Fail'(Command)                         If we put Total Marks. = 325, the decision will be as 'Pass'              Every function is differentiated by its symbols or sign used. The following are the sign of that function which consists of very few numbers of sign '>', '<', '=' are the sign of which function.                (A) Mathematical                             (B) Arithmetical                                (C) Logical (D) Special   Answer: (c)                                                                         Explanation Correct Option:                                               (C) >, <, =: Given signs are used in logical function. Incorrect Options: (A) Mathematical function: signs are +, -, * and /   (B) Arithmetical function: f(n), x(n), etc are the arithmetical functions. (D) Special function: are the mathematical functions which have more or less established names.        There are many types of sign and symbols you daily use. Which among the following is not a symbol?       (A) = (B) < (C) * (D) a     Answer: (D) Explanation Correct Option: (D) a : Is not a symbol.                Incorrect Options:   (A) = : Is a logical symbol.                      (B) < : Is a logical symbol. (C) * : Is a mathematical symbol.          

• Thousands of years ago, men used fingers, stones or bones for counting. ABACUS was the first device used by man for calculations by using beads.   The Chinese invented ABACUS.    

     

• ABACUS: A language for interactive scientific computation.
• Calculator: A small hand-held computer that performs mathematical Calculations  

     

• A computer is a machine that solves computing more...

       Mathematical Functions     Suppose you went to the market to buy milk, bread and ice-cream and wish to know how much money you spent at the shop. For this, you need to add the cost for the various items to get the result. (See Figure 2.2.3)                             (A) 25 (milk) + 15 (bread) + 10 (ice-cream) = 50 (Amount spent) Similarly, if you went with seventy rupees and wish to know how much money is left with you, you need to subtract the amount that you spent from seventy. (B) 70 (amount in the beginning) - 50 (amount spent) = 20 (Amount left) these calculations can be performed by a computer also. The processes of addition (+), subtraction (-), multiplication (*) and division (/) to arrive at a mathematical result are called Mathematical Functions.                There are many signs used in mathematical function in a computer. What is the sign of multiplication in computer?   (A) *                                                                      (B) -                                                                                                       (C) +                                                                      (D) x   Answer: (a) Explanation Correct Option:  (A) *: is the sign used for the multiplication in computer. Incorrect Options: (B) -; use for subtraction. (C) + : use for addition.   (D) x - is a sign used manual for multiplication.          Replace appropriate operators in the following expression. (5x7) - (14 divided by 2) (A) (5x7) - (14% 2)                                            (B) (5*7) - (14-2)                                               (C) (5*7) - (14/2)                                              (D) None of these     Answer: (C)  Explanation Correct Option: (C) (5*7)-(14/2) Incorrect Options: (A) (5x7) - (14 % 2) - here % is a symbol of percentage, that's why it is incorrect. (B) (5*7) - (14 - 2) - here sign of subtraction is used instead of division that's why it is incorrect.

         Functions Performed by a Computer         You must have seen calculators which perform basic mathematical operations such as addition, subtraction, multiplication and division. Suppose you want to find the total marks of all the subjects in your examination (English - 85, Mathematics - 90, Science- 80 and Hindi -70), a calculator can quickly give you the answer as 325. However, a computer is a better calculating machine because it?s not only performs these mathematical operations, but also give some logical decisions.     For example, if we want to find out the grade you obtained, The computer can do it for us.            For executing this function, we give the following command: If Total Marks > 300; print 'FIRST DIVISION' The computer will deal with total marks, as directed and it will print the logical Results - FIRST DIVISION. So, a computer performs two types   of   functions mathematical function and logical function to complete the job of computation.           

     Caring Computer   Although the computer is a very powerful machine, but it needs special care in handling and one needs to look after it properly.         The following things should be kept in mind for the proper caring of corn outer:

• We should keep the computer system in a cool, dry and dust-free environment.
• We should not touch it by the wet hand.
• Our hands should be clean and dry before we touch the computer.
• We should not touch plugs or wires when the computer is ON.
• Do not pile things on top of the monitor or CPU.      

       How can you take proper computer?   (A) By keeping it in a hot room                  (B) By keeping it in a cool room (C) By piling things on monitor                   (D) All of these     Answer: (b) Explanation Correct Option: (B) We should keep computer at a cool place for its proper functioning. Therefore, option (b) is correct. Incorrect Options: (A) Option (A) is incorrect. (C) Option (C) is incorrect. (D) Option (D) is incorrect.        Given below are the two statements. Which one of the following options s correct for the given statements? Statement A: You should keep the computer away from dust. Statement B: You should keep the CPU in the air tight box while working. (A) Statement A is correct                             (B) Statement B is correct (C) Both statement A and Bare correct   (D) Both statement A and B are incorrect     Answer: (A) Explanation Correct Option: (A) We should keep the computer away from dust. Therefore, option (A) is correct. Incorrect Options: (B) Option (A) is incorrect. (C) Option (C) is incorrect. (D) Option (D) is incorrect.        

• A standard keyboard has 104 or more keys.
• The CPU is also called the 'Brain' of the computer.
• The Spacebar key is the longest key in the Keyboard.    

     

• Computer: An electronic machine that works very fast can do various tasks such as calculations, sending messages, storing information and executing instructions.
• CPU: Also referred to as the processor where calculations and decisions are made.
• Mouse: Is a primary input device used with the computer to point and select items and draw.
• Monitor: Also called 'computer screen' or 'display unit' this allows a user to interact with the computer.
• Keyboard: A board of keys which is a primary input device used with the computer.      

     

• The computer is a wonderful electronic machine that can perform various tasks more...

       Switching the Computer On and Off       Many people get nervous when they have to work on the computer for the first time but switching on a computer is as simple as switching on your television set at home.                                                                    Switching ON the Computer  

• Ensure that the main cable of the computer is plugged into the electricity mains socket.
• Press the Power button on the computer system box and the monitor to switch the power on.
• The computer will perform some startup checks and after a few moments,  the Windows desktop is displayed. The desktop is the first screen that you see on the computer when Windows has loaded.  

          Switching OFF the Computer   Once you have finished working on the computer you need to save your work and shut down the computer correctly so that your work is not lost.           To shut down the computer the following steps should be followed:

• Click Start button. (The Start button is at the bottom left corner of the desktop)
• When the Start menu appears, click Turn off Computer.
• When the Turn off Computer Windows dialog box appears, click Turn off. Use the Power switch to turn off the computer.  

         You must have noticed that a computer performs few actions automatically when you switch on power button. What does computer do when you switch on the power button of CPU and monitor? (A) The computer performs some start-up checks (B) The computer does not perform any start-up checks (C) The computer performs some start-up checks in case of any fault (D) All of these     Answer: (A) Explanation Correct Option: (A) The computer performs some start-up checks and after a few moments, the Windows desktop is displayed. Therefore, option (a) is correct. Incorrect Options: (B) Option (B) is incorrect. (C) Option (C) is incorrect. (D) Option (D) is incorrect.          There is a certain button that is clicked to switch on and off the computer. Which one of the following buttons is clicked to switch off the computer? (A) Program (B) Start (C) My computer (D) My document   Answer: (B) Explanation Correct option: (B) To switch off the computer first of all start button is clicked. Incorrect Options: (A) Option (A) is incorrect. (C) Option (C) is incorrect. (D) Option (D) is incorrect.  

        Opening and Closing Applications or Programs    Suppose you wanton make a beautiful birthday card for your friend. You can do this by using the Paint application which is a program in window          Opening the Paint Application       To open the paint application, perform the following task:                

• Click' Start 'button. (A list is displayed which is referred to as a menu from which you can select any program that
• From the menu, click 'Programs'.
• From this menu, click 'Accessories'.
• From this menu, click 'Paint'. (The Paint screen appears on the monitor in which you can draw your picture). (See Figure 2.1.7)  

         Closing the Paint Application  Now that you have completed making your picture, you need to save your work and exit from the Paint application.      For this, follow the given steps:  

• Click 'X' on the title bar of the Paint screen, located at the top right corner.
• A dialog box appears with the message - Save changes to untitled?
• Click 'Yes'.
• Type in a name at the File name box and then click Save button. (This will close the Paint application)

               Given below are the processes of drawing on computer in paint application. Which one of the following is correct process for drawing? (A) Click 'Start' button, click 'Accessories,' click 'Programs' and finally click 'Paint' to draw (B) Click 'Programs' click 'Start' button, , click 'Accessories' and finally click 'Paint' to draw (C) Click 'Paint', click 'Start' button, click 'Programs' and finally click 'Accessories' to draw (D) Click 'Start' button, click 'Programs', click 'Accessories' and finally click 'Paint' to draw   Answer: (d)   Explanation Correct Option: (D) To draw first of all click start button then click programs. After clicking programs click accessories and finally click paint to draw. Therefore, option (D) is correct. Incorrect Options: (A) Option (A) is incorrect. (B) Option (B) is incorrect. (C) Option (C) is incorrect.        Steve draws a card on computer and wants to use this card again and again. What should he do for this? (A) He should draw the card again and again (B) He should delete the work (C) He should save the work (D) All of these     Answer: (C) Explanation Correct Option: (C) To use the card again and again drawn on the computer we should save it. Incorrect Options: (A) Option (A) is incorrect. (B) Option (B) is incorrect. (D) Option (D) is incorrect.  

     The Keyboard   The Keyboard is a device to enter data into the computer. When you press the keys on the keyboard, the text appears on the screen. Generally the keys are of four types that you will study in the later part of the book, but here you will study about three types only because in this chapter alphabet keys and number keys have been combined as alphanumeric keys.         Therefore, the three categories of keys to handle the special functions required by  the computer are the following:

• Alphanumeric Keys (Alphabet and Numeric)
• Special Purpose Keys
• Function Keys  

     Alphanumeric Keys They consist of alphabets (A-Z), numbers (0-9) and other characters like ' ~ ! @ # $ % ^ & * ( )  _ + \  { }  [ ] : " ' , /  and ?. This can be divided into two types of keys- alphabetic and numeric keys.          The names of some special character keys are the following:       (@)   =     at the rate of (&)   =     ampersand (~)   =     tilde (#)    =     pound sign (number sign) (^)   =      caret (*)    =      asterisk (star) (")    =      quotes (')     =      apostrophe (!)     =     exclamation mark (%)   =     percent ($)    =     dollar (?)    =     question mark ( _ )  =     underscore (;)     =     semi colon (")    =     double quote (/)     =     slash (\)     =     back slash (+)    =     plus (- )    =     minus ( | )   =      Pipe (<)   =      less than (>)   =      greater than (:)     =      colon ( , )   =      comma ( [ )   =      open bracket ( ] )   =      close bracket ( { )   =      open brace                                 ( } )   =      close brace ( } )   =      open parenthesis                 ( ) )   =      close parenthesis                   Special Keys          They perform specific functions. Some special keys are Enter (return), Backspace, Insert, Delete, Home, End, etc.        Function Keys They are used to perform a set of operations using a single keystroke. The function keys can be defined as special more...

       Computer Basics   Computer is the most wonderful machine that has redefined the way of our living. It has not only helped in overcoming the geographical barrier but also made our work easier and faster.           The following are the features of a computer:

• It is a wonderful electronic machine.
• It works very fast, never makes mistakes, never gets tired and can remember and store a lot of information.
• It works on the principle of taking input (data entered in the computer), processing it using some programs and then delivering the output (the result produced based on the user input). It means first some data is entered in the computer. Then this data is processed with the help of some programs and finally output is delivered. Output here refers to result.
• It makes our work easier and helps us to do many things such as calculations, writing letters, playing games, watching movies, listening to music, drawing, sending messages and even shopping by using the Internet.
• It cannot think on its own or make decisions. It only follows the instructions given to it.   

             Given below the statements about computer. Which statement is correct about it? Statement A: Computer can store information. Statement B: Computer is similar to typewriter.     (A) Statement A is correct (B) Statement B is correct (C) Both statement A and Bare correct (D) Both statement A and B are incorrect     Answer: (A) Explanation Correct Option: (A) Computer can store information but it is different from typewriter Therefore, option (A) is correct.                                   Incorrect Options: (B) Option (B) is incorrect. (C) Option (C) is incorrect. (D) Option (D) is incorrect.          Computer is a wonderful machine, but it is different from humans. Which one of the following options is correct for this difference?     (A) Computer can work faster                    (B) Computer can store information             (C) Computer cannot think                          (D) All of these                                    Answer: (c)  Explanation          Correct Option: (C) Computer can not think but humans can think. Therefore, option (C) is correct. Incorrect Options: (A) Option (A) is incorrect. (B) Option (B) is incorrect. (D) Option (D) is incorrect. 

     Computers       Do you know what a computer is? Yes, computer is an electronic machine that helps us to make our work easier and faster by assisting us in many ways. Being an electronic device it is very faster and quicker. You will definitely enjoy working on it. Let us learn about our computer.                   Parts of Computer As our body is made up of different parts (head, neck, legs and hands), in the same way a computer is also made up of different parts. The four main parts of the computer are the Keyboard, Mouse, Monitor and the CPU (Central processing unit).  (See Figure 2.1.1)              Keyboard     The keyboard looks like a typewriter. It also works like a typewriter. It has many buttons called keys. It is used to type letters, words and numbers in the computer. (See Figure 2.1.2)              Mouse       The mouse of a computer has a power cord resembling a tail and looks like a real mouse. The mouse is used to move the pointer on the computer screen. It can also be used to select items and draw pictures on the computer. (See Figure 2.1.3)             Monitor     The monitor looks like a TV screen. It shows words, numbers, pictures and movies on the screen. It displays all the work that you do on the computer. It is also called Visual Display Unit or V D U. (See Figure 2.1.4)            CPU     The CPU looks like a box. CPU stands for Central Processing Unit. As you know that our brain controls all the activities in our body, similarly the CPU controls all the activities of the computer. The CPU has an ON/OFF switch and some other buttons on it. Some other parts of the computer are the speakers, printer, scanner, UPS and the joystick. (See Figure 2.1.5)                               Which one of the following is the part of computer that controls all the functions of the computer? (A) Desktop                                                        (B) CPU (C) Keyboard                                                     (D) Mouse     Answer: (b) Explanation Correct Option: (B) CPU: The role of CPU is similar to the role of brain in our body. CPU controls all the functions of computer. Therefore, option (B) is correct. Incorrect Options: (A) Desktop: Is the main screen of a computer. (C) Keyboard: Is the most more...

      Safety Rules   Safety rules are the rules which we need to follow for our own benefit and well-being. We must follow these rules everyday so that we can remain safe.            While Walking   Traffic Police (i) Always walk on the right side of the road. (ii) Walk on footpath. (iii) Always look for the safest place to cross the road. Zebra crossing or subways are the safest for crossing a road. (iv) Always STOP, LOOK and LISTEN for any approaching vehicle. If you need to wait, wait at the zebra crossing. WAIT till the road is clear. (v) While crossing the road, first look RIGHT, then LEFT, then again RIGHT. (vi) If possible, try to cross the road in a group or at least with some friends. (vii) Never run or play on the road.   For School Bus   (i) Always wait in a queue with other children for the bus. (ii) Get into the bus one by one. (iii) Once inside the bus, do not lean out of the door or window. (iv) Never get in or out of a moving bus.   While Riding a Bicycle (i) Keep to the left of the road. (ii) Give signal by hand before turning or stopping. (iii) If possible, wear a helmet.   On playground (i) Take turn to play and give a chance to others. (ii) Never play on a broken swing. Inform an adult if a swing is broken. Use your both hand while climbing a swing. (iii) Never climb up the front of a slide. (iv) Help to keep the playground clean.               Which one of the following is the cheapest means of land transport to cover long distance? (a) Car (b) Train (c) Truck (d) None of these   Answer: (b) Explanation  By train one can cover the longest distance with minimum expenditure. Therefore, option (B) is correct and rest of the options is incorrect.            If you want to go to moon which of the following means of transport will you use? (a) Aeroplane (b) Helicopter (c) Ship (d) Rocket   Answer: (d) Explanation  We all know that only by rocket one can reach moon. Therefore, option (D) is correct and rest of the options is incorrect.     In our neighborhood there are many services. Festivals bring the people neighbourhood together Trains are the cheapest means of land transport. We must follow the safety rules for our own benefits.