Chapter 8 Computer Languages & Problem Solving Techniques (Class 6)

 

Chapter 8

Computer Languages & Problem Solving Techniques

 

C. Answer in short.

 

1. What are binary digits?

Ans – A computer can understand only special signals, which are represented by 1s and 0s. These two digits are called binary digits.

 

2. Which generation uses a visual or graphical interface?

Ans – Fifth Generation uses a visual or graphical interface.

 

3. What do you understand by an algorithm?

Ans – Algorithm is the step-by-step instructions written in simple language to perform a particular task.

 

4. What is a flowchart?

Ans – Flow chart is a step-by-step process of representing the solution of a particular problem in a graphical or pictorial form.

 

D. Answer in detail.

1. What do you understand by computer languages? Name the different categories of computer languages.

Ans – Computers do not understand any other language that we speak. They understand programs written in special languages. The language which helps the user to communicate with computer is called Computer Language.

There are two categories of computer languages:

i) Low Level Language: Low level languages are the machine codes in which the instructions are given in machine language in the form of 0 & 1 to a computer system. Low level language is also divided into parts:- Machine language and Assembly language.

a) Machine Language - It is the first generation language developed for communicating with a computer. It is written in machine code which represents 0 and 1 binary digits.

b) Assembly Language - It is the second generation programming language developed for communicating with a computer. These language use letters and symbols instead of binary digits. Example- As

ii) High Level Language: The high level languages are the most used programming languages that help a programmer to read, write and maintain the codes. It is also the third generation language that is used by many programmers. Example – C,C++, SQL, Visual Basic, etc.

2. What is the difference between high level and low level languages?

Ans – The difference between high level and low level languages are:

 

3. What are the rules for writing an algorithm?

Ans – The rules for writing the algorithm are-

1.         Always begin with the step START and finish with STOP.

2.         Number the statements such as Step 1, Step 2, etc.

3.         Write each step in a separate line.

4.         Function of each statement should be very clear.

 

 

4. What is use of flowchart symbols- Processing box and Decision box?

Ans – Processing box: A rectangle represents the processing of instructions.

 

 

          Decision box: A diamond symbol is used to choose between the two options, yes or no.

 

 

5. Write algorithm for the following problems.

 

a. to read name and phone number and print both.

Ans – To read name and phone number and print both:

Step 1: Start

Step 2: Read name, phone no

Step 3: Print name, phone. No

Step 4: Stop

 

 

b. to read marks and print grade ‘A’ if marks >80 otherwise ‘B’.

Ans – . To read marks and print grade ‘A’ if marks > 80 otherwise ‘B’:

Step 1: Start

Step 2: Read marks

Step 3: If mark > 80

THEN

    grade  ‘A’

ELSE

      grade ‘B’

Step 4: Stop

 

Chapter 9 More About Internet (Class 4)

Chapter 9

More About Internet

C. Answer these questions.

1. What is a web browser? Name any two web browsers.
Ans - Web Browser is a software in your computer which is needed to open the web pages. The two popular web browsers are: Google Chrome and Mozilla Firefox.

2. What is online safety?
Ans - Online safety means being safe while using the Internet.

3. Write any three uses of Internet.
Ans - The three uses of Internet are:

• We can download or play online games.
• We can download movies, songs, games, etc.
• We can book tickets for a train, movies or a flight.

4. Differentiate between downloading and uploading.
Ans- 

Workbook Class 6 Science Chapter 12 Electricity and Circuits

Chapter 12
Electricity and Circuits

Exercise

I. Answer the following questions in brief:

Q.1 How does an electric cell produce electricity?
Ans - Electric cell produce electricity from the chemical stored inside it.

Q.2 How many terminals does an electric bulb have? Can you identify them?
Ans - Electric bulb have two terminals one is positive while the other is negative.

Q.3 Why does a fused bulb not glow?
Ans - In fused bulb the filaments break and current does not pass through it.

Q.4 Is air a conductor of electricity or an insulator? What about the human body?
Ans - Air is a insulator but under certain condition it can conduct electricity. Human body is a good conductor of electricity.

Q.5 Why should the two terminals of an electric cell not be joined directly without connecting them through a device like a bulb?
Ans - The two terminals of the electric cell are never joined together without connecting them thought a switch and a device like a bulb because if we do so the chemical in the electric cell get used up very fast and the cells stops working.

Q.6 How are the terminals of an electric bulb different from those of an electric cell?
Ans - In electric bulb the filament is attached to its two terminals whereas the electricity cell has its two terminals one is called positive while other is called negative.

Q.7 Give any two uses of insulators.
Ans - (a) Insulators are used for covering wires switches

(b) Insulators are used to make hand gloves to hold electrical appliances  

II. Give one term for each of the following:

a) Device to break or complete a circuit - Switch
b) Materials which allow electric current to pass through them. - Conductor
c) Path of electricity to pass - Circuit
d) Thin wire inside electric bulb which glows when current passes through it - Filament
e) Ends of electric bulb or cell. - Terminals
f) Materials which do not allow electric current to pass through them. - Insulators

III. Fill in the blanks:

a) A torch bulb has an outer case of  glass that is fixed on a metallic base.
b) The bulb glows only when current flows through it.
c) A switch is a simple device that either breaks the circuit or complete it.
d) An electric all produces electric from the chemicals stored inside it.
e) When the filament of a bulb breaks, it is said to be fused
f) Both the electric cell and bulb have two terminals each.

IV. State whether True or False

a) An electric bulb has two terminals: one is positive (+) and the other is negative (-). True
b) Human body is an insulator. False
c) The filament of a bulb is made of thick wire. False
d) Handles of a screw driver can be made of metals instead of plastic. False
e) Pure water is an insulator. False
f) We should never join the two terminals of an electric cell directly without connecting them through an electric device. True

V. Match the following:

a) Rubber - (iv)  Insulator
b) Cell - (vi) Positive and negative terminals
c) Switch - (i) Make or break circuit
d) Bulb - (iii) filament
e) Metal - (ii) conductor

VI. Select the Correct alternative:

(i) Gucci and Ricci set up the following apparatuses for showing how a switch works in an electrical circuit. Both the set ups were same except in one way. Gucci used a plywood base while Ricci used an iron base.

Which of the following are true?

Ans (d) Gucci's set up is correct while that of Ricci is not

(ii) Which of these is a conductor?

a) Human body   b) Air Metal    c) Water    d) All of these

Ans (d) All of these

(iii) For making electrical wires, we use the materials which are
Ans (a) conductors

(iv) While demonstrating the working of an electric circuit, the bulb does not glow. This may be because
Ans (d) any of these

(v) Electric current flows
Ans (b) From positive terminal to negative terminal

(vi) The handles of screw drivers are made of
Ans (c) any of these