ALU 101 Carry and Overflow

Question 1

What is a carry bit in binary addition?

Accepted Answer

A bit propagated to the next higher position when the sum exceeds 1

Answer

A bit that stores the result

Answer

A bit used for error correction

Answer

A bit that resets the accumulator

Question 2

A half adder computes which two outputs?

Accepted Answer

Sum and Carry

Answer

Sum and Overflow

Answer

Carry and Borrow

Answer

Sum and Borrow

Question 3

What additional input does a full adder have compared to a half adder?

Accepted Answer

Carry-in

Answer

Overflow bit

Answer

Borrow bit

Answer

Enable signal

Question 4

Adding 0111 + 0001 in 4-bit unsigned binary produces what result and carry?

Accepted Answer

Result=1000, Carry=0

Answer

Result=1000, Carry=1

Answer

Result=0111, Carry=1

Answer

Result=1001, Carry=0

Question 5

In a ripple carry adder, why does carry propagation slow down the circuit?

Accepted Answer

Each bit's carry must wait for the previous bit's carry to settle

Answer

Carry signals require extra power

Answer

The carry flip-flop needs clock synchronization

Answer

Carry bits travel over long wire distances

Question 6

Which adder architecture eliminates ripple carry delay by pre-computing carries?

Accepted Answer

Carry Lookahead Adder

Answer

Carry Save Adder

Answer

Wallace Tree Adder

Answer

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