Explore topic-wise InterviewSolutions in .

Input and Output Functions:

A program needs to interact with the user to accomplish the desired task; this can be achieved using Input – Output functions. The input ( ) function helps to enter data at run time by the user and the output function print ( ) is used to display the result of the program on the screen after execution. 

The print ( ) function 

In Python, the print Q function is used to display result on the screen. 

The syntax for print Q is as follows:

Example

print (“string to be displayed as output ”)

print (variable)

print (“String to be displayed as output ” , variable) 

print (“String1 ” , variable, “String 2” , variable, “String 3”)

Example

>>> print (“Welcome to Python Programming”) 

Welcome to Python Programming

>>> x = 5

>>> y = 6

>>> z = x + y

>>> print (z)

11

>>> print (“The sum = ” , z)

The sum = 11

>>> print (“The sum of” , x, “and” , y, “is” , z)

The sum of 5 and 6 is 11

The print ( ) evaluates the expression before printing it on the monitor. The print ( ) displays an entire statement which is specified within print ( ). Comma ( ,) is used as a separator in print ( ) to print more than one item.

input ( ) function

In Python, input ( ) function is used to accept data as input at run time. The syntax for input ( ) function is,

Variable = input (“prompt string”)

Where, prompt string in the syntax is a statement or message to the user, to know what input can be given. 

If a prompt string is used, it is displayed on the monitor; the user can provide expected data from the input device. The input ( ) takes whatever is typed from the keyboard and stores the entered data in the given variable. If prompt string is not given in input ( ) no message is displayed on the screen, thus, the user will not know what is to be typed as input.

Example 1:

input ( ) with prompt string

>>> city = input (“Enter Your City: ”)

Enter Your City: Madurai

>>> print (“I am from “ , city)

I am from Madurai

Example 2:

input ( ) without prompt string

>>> city = input ( ) 

Rajarajan

>>> print (I am from” , city)

I am from Rajarajan

Note that in example – 2, the input ( ) is not having any prompt string, thus the user will not know what is to be typed as input. If the user inputs irrelevant data as given in the above example, then the output will be unexpected. So, to make your program more interactive, provide prompt string with input ( ). 

The input ( ) accepts all data as string or characters but not as numbers. If a numerical value is entered, the input values should be explicitly converted into numeric data type. The int ( ) function is used to convert string data as integer data explicitly. We will leam about more such functions in later chapters.

Example 3:

x = int (input(“Enter Number 1: ”))

y = int (input(“Enter Number 2: ”))

print (“The sum = ” , x + y)

Output:

Enter Number 1:34

Enter Number 2:56

The sum = 90

Example 4:

Alternate method for the above program

x, y = int (input(“Enter Number 1 :”)), int(input(“Enter Number 2:”))

print (”X = “ ,x, ”Y = “ ,y)

Output:

Enter Number 1:30

Enter Number 2:50

X = 30 Y= 50

“‘ “‘ triple quotes

(b) Ferrous nitrate

Python breaks each logical line into a sequence of elementary lexical components called Tokens

Key features of Python:

It is a general purpose programming language which can be used for both scientific and non – scientific programming.

It is a platform independent programming language. The programs written in Python are easily readable and understandable

Keywords are special words used by Python interpreter to recognize the structure of program. As these words have specific meaning for interpreter, they cannot be used for any other purpose. Eg, While, if.

(c) Long integer uses upper and lower case 1.

Answer is (d) 0X102

Comments in Python

In Python, comments begin with hash symbol (#). The lines that begins with # are considered as comments and ignored by the Python interpreter. Comments may be single line or no multi – lines. The multiline comments should be enclosed within a set of # as given below.

# It is Single line Comment

# It is multiline comment

which contains more than one line #

(a) 1 – (ii), 2 – (iv), 3 – (i), 4 – (iii)

(b) Built – in

There are 2 floating point values in a complex number

false, class, none, continue, finally, return, is

1. An identifier must start with an alphabet (A..Z or a..z) or underscore (_).

2. Identifiers may contain digits (0 .. 9) 

3. Python identifiers are case sensitive i.e. uppercase and lowercase letters are distinct.

4. Identifiers must not be a python keyword.

5. Python does not allow punctuation character such as %,$, @ etc., within identifiers.

Example 1:

input ( ) with prompt string

>>> city = input (“Enter Your City: ”)

Enter Your City: Madurai

Example 2:

input ( ) without prompt string

>>> city = input ( )

Rajarajan

The syntax for inputQ function is,

Variable = input (“prompt string”)

Where, prompt string in the syntax is a statement or message to the user, to know what input can be given.

If a prompt string is used, it is displayed on the monitor; the user can provide expected data from the input device. The input) ) takes whatever is typed from the keyboard and stores the entered data in the given variable. If prompt string is not given in input() no message is displayed on the screen

The syntax for print ( ) is as follows:

Example:

print (“string to be displayed as output ” )

print (variable)

print (“String to be displayed as output ” , variable) 

print (“String 1 ” , variable, “String 2” , variable, “String 3”)

Answer is Comments

(a) Whitespaces

The metal used in electroplating is Cu

(c) Cu₂S + FeS

(a) Potassium

(a) Pure alumina + molten cryolite + fluorspar

A have the lowest ionization energy

(c) galvanization

(c)  2, 8, 8, 1

Single, multi

(b) Calcium oxide

(b) Assertion is correct, Reason is wrong.

(c) Baeyer’s process

Tungsten is not a good conductor of heat and electricity. 

(i) Bauxite ore is finely ground and heated under pressure with a solution of concentrated caustic soda solution at 150°C to obtain sodium meta aluminate. 

(ii) On diluting sodium meta aluminate with water, a precipitate of aluminium hydroxide is formed.

(iii) The precipitate is filtered, washed, dried and ignited at 1000°C to get alumina.

2Al(OH)₃ + 1000°C ⟶ Al₂O₃ + 3H₂O

CaF₂ (Fluorspar) is added along with cryolite and alumina. It is added to reduce the high melting point of the electrolyte.

(d) Assertion and Reason are correct, Reason doesn’t explains Assertion.

• By fusing the metals together. 

E.g. Brass is made by melting zinc and copper. 

• By compressing finely divided metals. 

E.g. Wood metal: an alloy of lead, tin, bismuth and cadmium powder is a fusible alloy.

(d) Assertion and Reason are correct, Reason doesn’t explains Assertion.

Caustic alkali is added to bauxite, to dissolve bauxite ore and obtain a solution of sodium aluminate.

(a) Assertion and Reason are correct, Reason explains the Assertion.

1. lead

2. aluminium

3. Iron silicate or FeSiO₃

4. 98%

5. hydraulic

The roasted ore of copper is mixed with powdered coke and sand and is heated in a blast furnace to obtain matte (Cu₂S + FeS) and slag. The slag is removed as waste. 

2 FeS + 3O₂ → 2 FeO + 2 SO₂ 

2 Cu₂S + 3O₂ → 2 Cu₂O + 2SO₂ 

Cu₂O + FeS → Cu₂S + FeO

FeO + SiO₂ → FeSiO₂ (slag)

1. To modify appearance and colour. 

2. To modify chemical activity. 

3. To lower the melting point.

4. To increase hardness and tensile strength. 

5. To increase resistance to electricity

A – Silvery white metal – Aluminium 

4 Al + 3O₂ ⟶ 2Al₂O₃(B) (Aluminium oxide)

The alloys of aluminium, Duralumin and Magnalium are used in making the aircraft. 

A – Aluminium; B – Aluminium oxide.

(i) The presence of water and oxygen is essential for the rusting of iron. 

(ii) Impurities in the iron, the presence of water vapour, acids, salts and CO₂ speeds up rusting.

The corrosive action in the presence of moisture is called wet corrosion. It occurs as a result of electrochemical reaction of metal with water or aqueous solution of salt or acids or bases.

Corrosion is the gradual destruction of metals by chemical or electrochemical reaction with the environment.

It is the method of controlling corrosion of a metal surface protected is coated with the metal which is easily corrodible. The easily corrodible metal is called Sacrificial metal to act as anode ensuring cathodic protection.

1.True

2. True 

3. True 

4. False – Reactive metals always occur in the combined state. 

5. False – Malachite is the carbonate ore of copper. 

6. False – Lanthanides are present in the 6th period of the periodic table. 

7. False – Atomic radius increases as we go across the period due to decrease in size. 

8. True 

9. False – If the difference in electronegativity is greater than 1.7, the bond is considered to be ionic. 

10. False – Siderite is the carbonate ore of Iron.

Smelting is a process of reducing the roasted metallic oxide to metal in a molten condition. In this process, impurities are removed by the addition of flux as slag.

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. 

4Fe + 3O₂ + xH₂O → 2Fe₂O₃ . xH₂O (Rust)