logical operations

Question 1

go through questions

Answer 1

go through questions

Question 2

Boolean values

Answer 2

False or True

0 or 1

Question 3

What does the AND function return

Answer 3

Returns true (1) if both values are true(1), otherwise returns false (0)

Question 4

What does the symbol for the AND function look like

Answer 4

D shape

Question 5

What does the OR function return

Answer 5

Returns true(1) if either values are true(1), returns false if both values are false

Question 6

What does the symbol for the OR function look like

Answer 6

Moon crest

Question 7

What does the NOT function return

Answer 7

Only takes one input (unlike the others) and reverses it

Question 8

What does the symbol for the NOT function look like

Answer 8

Sideways triangle

Question 9

What does the NAND function return

Answer 9

NOT AND

Returns false(0) only if both values are true(1), otherwise returns true(1)

Carries out an AND operation and performs a NOT on the result (reverses it)

Question 10

What does the NAND symbol look like

Answer 10

D symbol with tiny circle on output

Question 11

What does NOR output

Answer 11

Returns true (1) if both values are false(0), returns false(0) if either values are true(1)

Carries out an OR operation then performs a NOT on the result (reverses it)

Question 12

What does a XOR output

Answer 12

Exclusive OR

Same as OR, returns 1 if either value is 1

However does not return 1 if both values are 1

Question 13

What does XOR symbol look like

Answer 13

moon crest with parallel curvy line on left

Question 14

How do bitwise operations work

Answer 14

Bitwise operations work by applying the operation successfully to each pair of binary digits

Question 15

How is OR written in boolean algebra

Answer 15

+

Question 16

How is AND written in boolean algebra

Answer 16

.

Question 17

How is not represented in boolean algebra

Answer 17

Overlining the letter
_
X

Question 18

Logical operations in control systems

Answer 18

Bits are used to represent on/off

Can be changed using AND, OR, XOR operations

each bit of a register or registers is linked (usually wiring) to a device

If a bit has a 1 entered then this could cause the particular device attached to be turned on, a 0 could be used to turn it off.

Question 19

What is masking

Answer 19

Masking always uses AND

It is used to check the values of particular bits

Question 20

How do you clear a register

Answer 20

ANDing with 0 always set the value to 0

Question 21

How do you reverse bits

Answer 21

XOR reverses the bits

Question 22

How do you encrypt words using XOR, AND etc.

Answer 22

E.g. encrypt BAD using XOR

Using an symmetric encryption/decryption key e.g. 01110010

BAD = 01000010 01000001 01000100
XOR XOR XOR
Key = 01110010 01110010 00110110
=48 =51 =54

Encrypted word is : 036

Question 23

What formate can AND be written in

Answer 23

A AND B
A.B
AB
A()

Question 24

What formats can OR be written in

Answer 24

A OR B

A+B

Question 25

What formats can you write NOT in

Answer 25

NOT A
_
A

Question 26

What is NOT(A AND B) in a different notation

Answer 26

_____

A . B

Question 27

What are identities used for in boolean algebra

Answer 27

Help us simplify expressions

Question 28

What is the commutative law

Answer 28

Expressions such as C+B is the same as B+C

I.e. the order doesn’t matter

Question 29

What is the associative law

Answer 29

A + (B+C) is the same as (A+B) + C

A(BC) is the same as (AB)C

Question 30

What is de Morgans law

Answer 30

Rule 1

___ _ _
P.Q = P + Q

rule 2

_____ _ _
P + Q = P.Q

break the line change the sign

Question 31

What is the essential characteristics of a key

Answer 31

The key is the secure binary number (only known to the sender and recipient)

Can only decrypt/read if the key is known