79. AQA GCSE (8525) SLR13 – 3.3 Binary shifts

What happens when you perform a binary left shift?

• The number is squared

• The number remains unchanged

• The number is multiplied by 2

• The number is divided by 2

Answer explanation

Performing a binary left shift on a number multiplies it by 2, shifting all bits to the left and adding a 0 at the rightmost position.

What is the result of left shifting the binary number 22 by one bit?

• 88

• 11

• 44

• 22

Answer explanation

Left shifting a binary number by one bit is equivalent to multiplying the number by 2. Therefore, left shifting 22 by one bit results in 44.

How many bits can you shift at a time?

• You cannot shift bits

• More than 2 bits

• Only 2 bits

• Only 1 bit

Answer explanation

You can shift more than 2 bits at a time, making the correct answer choice 'More than 2 bits'.

What fills the empty slot on the far right after a left shift?

• It remains empty

• 0

• The last bit

• 1

Answer explanation

After a left shift, the empty slot on the far right is filled with a 0, making 0 the correct choice.

What is the effect of a binary right shift?

• Subtraction by 2

• Remains the same

• Division by 2

• Multiplication by 2

Answer explanation

A binary right shift operation divides a number by 2, shifting all bits to the right and discarding the least significant bit.

What happens to the bits that disappear off the left-hand side during a shift?

• They are lost

• They move to the right-hand side

• They are added back on the right

• They are stored for later use

Answer explanation

During a shift, the bits that disappear off the left-hand side are lost.

What is used to pad the leading space after a binary right shift?

• 0

• The last bit

• 1

• It remains unpadded

Answer explanation

The leading space after a binary right shift is padded with 0, making 0 the correct choice.

What mathematical operation does a binary left shift resemble?

• Division

• Multiplication

• Subtraction

• Addition

Answer explanation

A binary left shift resembles multiplication because shifting a binary number to the left by one position is equivalent to multiplying it by 2.

What mathematical operation does a binary right shift resemble?

• Addition

• Subtraction

• Division

• Multiplication

Answer explanation

A binary right shift resembles division because it is equivalent to dividing the number by 2 raised to the power of the shift amount.

What is the result of right shifting the binary number 22 by one bit?

• 11

• 33

• 44

• 22

Answer explanation

Right shifting the binary number 22 by one bit results in 11. This is because shifting a binary number to the right by one bit is equivalent to dividing the number by 2.