CBSE Guess > Papers > Important Questions > Class XII > 2011 > Computer Science > Computer Science By Mr. Kapil Bhatia
CBSE CLASS XII
Basic Theory (Part 2)
Page 7 of 7
- Define Queue and Stack.
Stack: A stack is a LIFO structure and physically it can be implemented as an array or linked list. When a stack is implemented, insertion and deletion take place only from one end ie. The stack top.
A queue is a FIFO type non-primitive linear data structure with two open ends, one called the Front where data is accessed and another called the Rear, from where data is added.
- What do you understand about a member function? How does a member function differ from an ordinary function?
Ans: a member function is the set of operations that are applied to objects of that class. A class may have zero or more member functions. they are also referred as class interface. An ordinary function is set of statement enclosed within curly braces and can be accessed by an ordinary variable. No security is provided in an ordinary function.
- Define primary key ,candidate key and alternate key.
Ans: the primary key is a column or a group of column that contain data, which is unique. There can be only one primary key per table. Every table must have a primary key. The primary key should not be NULL.
Those key fields that can be serve as a primary key called candidate key.
Out of multiple candidate keys, only one candidate key act as a primary key in a relation and the remaining candidate key is/are called alternate key.
- What is the purpose of using a gateway?
Ans. The gateway is used to connect two network of different type. It operates at the level of application of OSI model. A gateway like a router, find the optimal path for message directed to a specific node in different network.
- Write an advantage and disadvantage of using fiber optic cable.
Ans it has higher capacity and low loss medium.
Disadvantage: This is expensive, difficult to join and connectors are expensive.
- Define term cardinality and degree?
Ans. The number of tuples(rows) in a relation is called cardinality of the relation. The number of attributes in a relation is called degree of the relation.
- Define co-axial cable and fiber optical cable?
Ans: coaxial cable are group of specially wrapped and insulated wire line that are able to transmit data at high rates. They consist of a central copper wire surrounded by a PVC insulation over which a sleeve of copper mesh is placed.
Optical fiber consists of fiber optical cable that is made of tiny threads of glass or plastic. The light waves are transmitted over the fiber.
- What do you understand by the term cookies and firewall?
Ans. Cookies: Cookies are the bits of data put on a hard disk when some on visit certain web sites. The cookies on the hard disk have the username and password in it, so people don’t have to log in.
Firewall: It is the system to prevent unauthorized access to / form a network.
- What is the importance of cyber law?
Ans: cyber law is an agreement between two parties making transmission using cyber technologies. Like any other law cyber law is enforced over all activities performed in which computer play a vital role. Any such activity which is proved to be happened by breaking the clauses of cyber law is punishable act and suitable punishment can be awarded under cyber crime act and section before the court of law.
- Difference between Hackers and Crackers.
Hackers: These are the persons who get unauthorized access to the websites and replace them with other website or unlawful information.
Crackers: The person by using certain software to trap authenticated information or crack the security code such as username and password to illegally access the information on computer are called crackers.
- What is a circular queue and how it is different from ordinary queue?
Ans: circular queue are the queues implemented in a circular form rather than a straight line in these queue the last element if followed by the first element.
- What is the difference between typecasting and automatic type conversion? Explain with suitable example.
Ans: Type Casting: It is an user define explicit type conversion in which operand in an expression is forced to be of a specific data type e.g. (type)expression
Automatic type conversion: In case of an expression in which operands different data type are mixed an implicit type conversion is performed by the compiler which automatically converts all operands upto the type of largest operands.
- How is an e-mail different from a chat?
Ans: e-mail is used to send and receive messages electronically in which sender and recipient need not to be online at the same time. The message are accumulated at the receiver’s mail box and can be retrieved at any lates time. Attachments of other document is possible in E-mail. Chat:
In chatting, to send and receive messages, both the sender and receiver must be online and available over the internet simultaneously, no record maintainer is available in chatting and no document attachment is provided on it.
- Define intranet?
Ans: An intranet is a private network that is contained within an enterprise It may consist of many interlinked local area networks and also use leased lines in the wide area network Typically, an intranet includes connections through one or more gateway computers to the outside Internet. The main purpose of an intranet is to share company information and computing resources among employees. An intranet can also be used to facilitate working in groups and for teleconferences
Submitted By Mr. Kapil Bhatia
Email Id : [email protected]
