Science (English Medium) Class 12 - CBSE Question Bank Solutions for Computer Science (Python)

List some common signs of malware infection.

List some preventive measures against malware infection.

What are the main components of data communication?

Assertion (A): CSV (Comma Separated Values) is a file format for data storage that looks like a text file.

Reason (R): The information is organized with one record on each line and each field is separated by a comma.

Atharva is a Python programmer working on a program to find and return the maximum value from the list. The code written below has syntactical errors. Rewrite the correct code and underline the corrections made.

def max_num (L):
        max=L(O)
        for a in L:
                if a > max
                 max=a
        return max

Write one difference between CSV and text files.

The code given below accepts a number as an argument and returns the reverse number. Observe the following code carefully and rewrite it after removing all syntax and logical errors. Underline all the corrections made.

define revNumber (num) :
      rev = 0
      rem = 0
      While num > 0:
            rem ==num %10
            rev = rev*10 + rem
            num = num//10
            return rev
print (revNumber (1234))

How are text files different from binary files?

Observe the following tables VIDEO and MEMBER carefully and write the name of the RDBMS operation out of (i) SELECTION (ii) PROJECTION (iii) UNION (iv) CARTESIAN PRODUCT, which has been used to produce the output as shown below. Also, find the
Degree and Cardinality of the final result.

TABLE: VlDEO

TABLE: MEMBER

TABLE: FINAL RESULT

The number of tuples in a relation is called ______.

Consider the code given below and fill in the blanks.

print (" Learning Exceptions…")
try:
    num1 = int(input ("Enter the first number")
    num2 = int(input("Enter the second number"))
    quotient=(num1/num2)
    print ("Both the numbers entered were correct")
except ________:           # to enter only integers
    print (" Please enter only numbers")
except __________:       # Denominator should not be zero
    print(" Number 2 should not be zero")
else:
    print(" Great .. you are a good programmer")
___________________ :       # to be executed at the end
print(" JOB OVER… GO GET SOME REST")

All the branches of XYZ school conducted an aptitude test for all the students in the age group 14 - 16. There were a total of n students. The marks of n students are stored in a list. Write a program using a user defined function that accepts a list of marks as an argument and calculates the ‘x^th’ percentile (where x is any number between 0 and 100).You are required to perform the following steps to be able to calculate the ‘x^th’ percentile.

Note: Percentile is a measure of relative performance i.e. It is calculated based on a candidate’s performance with respect to others. For example: If a candidate's score is in the 90^th percentile, that means she/he scored better than 90% of people who took the test.

Steps to calculate the x^th percentile:

I. Order all the values in the data set from smallest to largest using Selection Sort. In general any of the sorting methods can be used.

II. Calculate index by multiplying x percent by the total number of values, n.
For example: to find 90^th percentile for 120 students: 0.90*120 = 108

III. Ensure that the index is a whole number by using math.round()

IV. Display the value at the index obtained in Step 3.

The corresponding value in the list is the x^th percentile.

Write a program that takes as input a list of 10 integers and a key value and applies binary search to find whether the key is present in the list or not. If the key is present it should display the position of the key in the list otherwise it should print an appropriate message. Run the program for at least 3 different key values and note the results.

Estimate the number of key comparisons required in binary search and linear search if we need to find the details of a person in a sorted database having 230 (1,073, 741, 824) records when details of the person being searched lie at the middle position in the database. What do you interpret from your findings?

Differentiate between structured and unstructured data giving one example.

The principal of a school wants to do the following analysis on the basis of food items procured and sold in the canteen:

1. Compare the purchase and sale prices of fruit juice and biscuits.
2. Compare sales of fruit juice, biscuits, and samosa.
3. Variation in the sale price of fruit juices of different companies for the same quantity (in ml).

Create an appropriate dataset for these items (fruit juice, biscuits, samosa) by listing their purchase price and sale price. Apply basic statistical techniques to make the comparisons.

Give the term for the following:

Software that is used to create, manipulate and maintain a relational database.

Compared to a file system, how does a database management system avoid redundancy in data through a database?

What are the limitations of the file systems that can be overcome by a relational DBMS?

For the above-given database STUDENT-PROJECT, can we perform the following operation?

Insert a project detail without a submission date.

Using the sports database containing two relations (TEAM, MATCH_DETAILS) and write the Query for the following:

Change the name of the relation TEAM to T_DATA. Also, change the attributes TeamID and TeamName to T_ID and T_NAME respectively.