AQA A level computer - All topics

Which of the following statements fully describes data in 2NF:

• When any repeating fields have been removed and the table is given a primary key

• When all repeating entries of data are removed and the fields in each table are directly related to the primary key and no fields are present that are not related to each other

• When all the fields in each table are directly related to the primary key

What is a foreign key?

• A unique identifier in a database

• A primary key of one table that appears in another table

• A field that should not be in a table and needs removing

A relation is in 1NF if it doesn't contain any ____________?

• Determinants

• Repeating groups

• Null values in primary key fields

• Functional dependencies

What is a relational database?

• A database that is built from a set of unique tables containing data about one entity
•  A database with one single large table
•  A set of many databases about numerous, related topics

What is 0.125 in fixed point binary (4 bits for the whole number / 4 bits for fractional part)?

• 10001000

• 00000010

• 00001000

• 00011000

What happens in FETCH immediately after the CPU reads the contents of the Program Counter to find the address of the next instruction to be fetched

• The Program Counter is copied to the CIR

• The Program Counter is incremented

• The contents of the data bus is read

• The contents of the MDR is read

What is a multitasking computer?

• Multiple users can be logged in at the same time

• A CPU core that can run more than one process at a time

• Multiple programs can be running at the same time

• A computer that can handle multiple input devices.

Communication rules used by network devices is known as protocol.

• True

• False

Which of these is NOT a condition of the Vernam Cipher offering "perfect" security?

• The key must be (at least) as long as the data to be encrypted/plaintext

• The key must not be reused

• The key must be (truly) random

• The key must only be made up of symbols and not letters or numbers

Is public key / private key encryption symmetric or asymmetric encryption?

• Symmetric

• Asymmetric