If the .................... is too much, the receiver may not be able to detect the signal at all or the signal may fall below the noise level.
Noise
Delay
Dispersion
Attenuation
Correct Answer :
D. Attenuation
Related Questions
A logical description of some portion of database that is required by a user to perform task is called as
System View
User View
Logical View
Data View
Datalog is
procedural query language
nonprocedural query language
scan(), write()
none of the above
The privilege lists include
i) select
ii) insert
iii) update
iv) delete
only i)
only i) ii)
only i) ii) iii)
i) ii) iii) iv)
The access protocol used by traditional Ethernet
CSMA/CA
CSMA/CD
CSMA
Token ring
The types of noiseless channels are
i) Selective Reject ARQ
ii) simplest protocol
iii) Go-Back-N ARQ
iv) Stop-and-Wait Protocol
i, ii only
ii and iv only
ii and iv only
i, iv only
Related fields in a database are grouped to form a
data file.
data record.
menu.
bank.
Electromagnetic spectrum included in radiowaves are
i) Super High Frequency (SHF)
ii) Very High Frequency (VHF)
iii) Ultra High Frequency (UHF)
iv) High Frequencies (HF)
i, ii and iii only
i, ii and iv only
ii, iii and iv only
i, iii and iv only
In this data model each record can hae more than one parent
Hierarchical model
E-R model
Network based model
none of these
In E-R diagram Generalization is represented by
Circle
Rectangle
Hyperbola
Triangle
A transaction which completes successfully is called
Granted
Committed
Compensated
Accomplished
Tertiary storage
magnetic tape
juke box
optical disk
All of the above
Which one of the following statements is false?
The data dictionary is normally maintained by the database administrator.
Data elements in the database can be modified by changing the data dictionary.
The data dictionary contains the name and description of each data element.
The data dictionary is a tool used exclusively by the database administrator.
The overall design of a database is called
Subschema of the database
Schema of the database
Structure of the database
View of the database
Which of the following operator preserves unmatched rows of the relations being joined?
Inner join
Outer join
union
Intersect
What is the result of the following SQL statement ?
SELECT A.emp_Name, B.ph_num
FROM emp A LEFT OUTER JOIN phone B
ON A. emp_ID = B.emp_ID
A list of employees phone number
A list of all employees that have spouses, with phone number included in the list
A list of all employees names, including the phone number if they have one
Two lists : One list of employees, the other of phone numbers
Encoding method which does not provide for synchronization
B8ZS
Manchester
RZ
NRZ-L
If the .................... is too much, the receiver may not be able to detect the signal at all or the signal may fall below the noise level.
Noise
Delay
Dispersion
Attenuation
The command used to delete a particular column in a relation
UPDATE
DROP
ALTER
DELETE
By default a user who has been granted some form of authorization
is allowed to pass them to others
is not allowed to pass them to others
may be or may not be allowed to pass them to others
none
The class based addressing is known as
Classless addressing
Classful addressing
Classified addressing
Classical addressing
Volatile storage
loses its contents when power is switched off.
doesnt loses its contents when power is switched off.
creates backup when power is switched off.
none
Referential integrity
controls relationships between operations of an object
controls relationships between instances of a class
controls relationships between attributes in a table
controls relationships between tables in a database
Disk storage is referred to as
sequential access storage
direct access storage
random access storage
none of the above
In two-phase locking protocol the two phases are
growing phase and shrinking phase
execution phase and blocking phase.
running phase and sleeping phase.
none of the above
A data manipulation command the combines the records from one or more tables is called
SELECT
PROJECT
JOIN
PRODUCT
EEPROM
Electrically Extractable Programmable Read Only Memory
Electrically Erasable Programmable Read Only Memory
Electronically Erasable Programmable Read Only Memory
Electrically Erasable Programmable Read Only Memory
Three SQL, DDL, CREATE commands are
Schema, Base and Table
Schema, Table and View
Base, Table and Schema
Key, Base and Table
A logical schema
is the entire database.
is a standard way of organizing information into accessible parts.
describes how data is actually stored on disk.
both A) and C)
Only one communication channel is needed rather than n channels to transmit data between two communicating devices
parallel
serial
analog
digital
Extended Entity Relationship model consists of which of the following
i) Specialization
ii) Generalization
iii) Categorization
i and ii only
ii and iii only
i and iii only
All i, ii iii