# Quantum Information Processing MCQs with Answers

What is the fundamental unit of quantum information?

a) Qubit

b) Bit

c) Quantum gate

d) Quantum circuit

**Answer: ** Answer: a) Qubit

In quantum computing, a qubit can exist in:

a) Only the state 0

b) Only the state 1

c) Both the states 0 and 1 simultaneously

d) Neither the state 0 nor 1

**Answer: ** Answer: c) Both the states 0 and 1 simultaneously

Which property of qubits allows for quantum superposition?

a) Entanglement

b) Coherence

c) Decoherence

d) Measurement

**Answer: ** Answer: b) Coherence

What is the term used for the entanglement of qubits across long distances?

a) Quantum teleportation

b) Quantum entanglement

c) Quantum superposition

d) Quantum gate

**Answer: ** Answer: b) Quantum entanglement

Which principle states that the act of measuring a qubit collapses its superposition into a definite state?

a) Pauli exclusion principle

b) Heisenberg uncertainty principle

c) Measurement principle

d) No-cloning theorem

**Answer: ** Answer: c) Measurement principle

What is the term used for the basic operations performed on qubits in quantum computing?

a) Quantum gates

b) Quantum circuits

c) Quantum algorithms

d) Quantum measurements

**Answer: ** Answer: a) Quantum gates

Which quantum gate is equivalent to the classical NOT gate?

a) Hadamard gate

b) Pauli-X gate

c) CNOT gate

d) Toffoli gate

**Answer: ** Answer: b) Pauli-X gate

What is the term used for the process of encoding information into a quantum state?

a) Quantum measurement

b) Quantum error correction

c) Quantum encoding

d) Quantum superposition

**Answer: ** Answer: c) Quantum encoding

Which property of qubits allows for quantum teleportation?

a) Entanglement

b) Coherence

c) Decoherence

d) Measurement

**Answer: ** Answer: a) Entanglement

Which quantum algorithm provides exponential speedup for factoring large numbers?

a) Grover’s algorithm

b) Shor’s algorithm

c) Quantum Fourier transform

d) Deutsch-Jozsa algorithm

**Answer: ** Answer: b) Shor’s algorithm

Which principle states that it is impossible to clone an unknown quantum state perfectly?

a) Pauli exclusion principle

b) Heisenberg uncertainty principle

c) No-cloning theorem

d) Measurement principle

**Answer: ** Answer: c) No-cloning theorem

Which type of quantum error correction code is used to protect qubits from arbitrary errors?

a) Stabilizer codes

b) Topological codes

c) Concatenated codes

d) Surface codes

**Answer: ** Answer: a) Stabilizer codes

Which property of qubits allows for quantum teleportation?

a) Entanglement

b) Coherence

c) Decoherence

d) Measurement

**Answer: ** Answer: a) Entanglement

Which quantum gate is used to create superposition?

a) Hadamard gate

b) Pauli-X gate

c) CNOT gate

d) Toffoli gate

**Answer: ** Answer: a) Hadamard gate

Which property of qubits allows for quantum entanglement?

a) Entanglement

b) Coherence

c) Decoherence

d) Measurement

**Answer: ** Answer: a) Entanglement

Which quantum algorithm is used for searching an unsorted database with a quadratic speedup?

a) Grover’s algorithm

b) Shor’s algorithm

c) Quantum Fourier transform

d) Deutsch-Jozsa algorithm

**Answer: ** Answer: a) Grover’s algorithm

Which principle states that the more precisely the position of a particle is known, the less precisely its momentum can be known?

a) Pauli exclusion principle

b) Heisenberg uncertainty principle

c) Measurement principle

d) No-cloning theorem

**Answer: ** Answer: b) Heisenberg uncertainty principle

Which property of qubits is susceptible to environmental disturbances and leads to loss of quantum coherence?

a) Entanglement

b) Coherence

c) Decoherence

d) Measurement

**Answer: ** Answer: c) Decoherence

Which type of quantum gate is used to perform controlled-NOT operations?

a) Hadamard gate

b) Pauli-X gate

c) CNOT gate

d) Toffoli gate

**Answer: ** Answer: c) CNOT gate

Which principle states that the state of a quantum system remains constant during the unitary evolution?

a) Pauli exclusion principle

b) Heisenberg uncertainty principle

c) Measurement principle

d) Schrödinger’s equation

**Answer: ** Answer: d) Schrödinger’s equation

Which type of quantum error correction code is based on non-Abelian anyons?

a) Stabilizer codes

b) Topological codes

c) Concatenated codes

d) Surface codes

**Answer: ** Answer: b) Topological codes

Which property of qubits allows for the possibility of quantum parallelism?

a) Entanglement

b) Coherence

c) Decoherence

d) Measurement

**Answer: ** Answer: b) Coherence

Which quantum gate is used to perform a controlled-phase shift?

a) Hadamard gate

b) Pauli-Z gate

c) CNOT gate

d) Toffoli gate

**Answer: ** Answer: b) Pauli-Z gate

Which principle states that the act of measuring a qubit does not disturb its superposition?

a) Pauli exclusion principle

b) Heisenberg uncertainty principle

c) Measurement principle

d) No-cloning theorem

**Answer: ** Answer: c) Measurement principle

Which type of quantum error correction code is obtained by concatenating multiple smaller codes?

a) Stabilizer codes

b) Topological codes

c) Concatenated codes

d) Surface codes

**Answer: ** Answer: c) Concatenated codes

Which property of qubits allows for quantum teleportation?

a) Entanglement

b) Coherence

c) Decoherence

d) Measurement

**Answer: ** Answer: a) Entanglement

Which quantum algorithm is used for solving problems with a yes/no answer with a single query?

a) Grover’s algorithm

b) Shor’s algorithm

c) Quantum Fourier transform

d) Deutsch-Jozsa algorithm

**Answer: ** Answer: d) Deutsch-Jozsa algorithm

Which principle states that it is impossible to simultaneously know the precise values of complementary variables of a quantum system?

a) Pauli exclusion principle

b) Heisenberg uncertainty principle

c) Measurement principle

d) No-cloning theorem

**Answer: ** Answer: b) Heisenberg uncertainty principle

Which property of qubits allows for quantum entanglement?

a) Entanglement

b) Coherence

c) Decoherence

d) Measurement

**Answer: ** Answer: a) Entanglement

Which quantum gate is used to perform a controlled-Hadamard operation?

a) Hadamard gate

b) Pauli-X gate

c) CNOT gate

d) Toffoli gate

**Answer: ** Answer: c) CNOT gate

Which principle states that the act of measuring a qubit collapses its superposition into a definite state?

a) Pauli exclusion principle

b) Heisenberg uncertainty principle

c) Measurement principle

d) No-cloning theorem

**Answer: ** Answer: c) Measurement principle

Which type of quantum error correction code is used to protect qubits from arbitrary errors?

a) Stabilizer codes

b) Topological codes

c) Concatenated codes

d) Surface codes

**Answer: ** Answer: a) Stabilizer codes

a) Entanglement

b) Coherence

c) Decoherence

d) Measurement

**Answer: ** Answer: a) Entanglement

Which quantum gate is used to create superposition?

a) Hadamard gate

b) Pauli-X gate

c) CNOT gate

d) Toffoli gate

**Answer: ** Answer: a) Hadamard gate

Which property of qubits allows for quantum entanglement?

a) Entanglement

b) Coherence

c) Decoherence

d) Measurement

**Answer: ** Answer: a) Entanglement

Which quantum algorithm is used for searching an unsorted database with a quadratic speedup?

a) Grover’s algorithm

b) Shor’s algorithm

c) Quantum Fourier transform

d) Deutsch-Jozsa algorithm

**Answer: ** Answer: a) Grover’s algorithm

Which principle states that the more precisely the position of a particle is known, the less precisely its momentum can be known?

a) Pauli exclusion principle

b) Heisenberg uncertainty principle

c) Measurement principle

d) No-cloning theorem

**Answer: ** Answer: b) Heisenberg uncertainty principle

Which property of qubits is susceptible to environmental disturbances and leads to loss of quantum coherence?

a) Entanglement

b) Coherence

c) Decoherence

d) Measurement

**Answer: ** Answer: c) Decoherence

Which type of quantum gate is used to perform controlled-NOT operations?

a) Hadamard gate

b) Pauli-X gate

c) CNOT gate

d) Toffoli gate

**Answer: ** Answer: c) CNOT gate

Which principle states that the state of a quantum system remains constant during the unitary evolution?

a) Pauli exclusion principle

b) Heisenberg uncertainty principle

c) Measurement principle

d) Schrödinger’s equation

**Answer: ** Answer: d) Schrödinger’s equation

Which type of quantum error correction code is based on non-Abelian anyons?

a) Stabilizer codes

b) Topological codes

c) Concatenated codes

d) Surface codes

**Answer: ** Answer: b) Topological codes

Which property of qubits allows for the possibility of quantum parallelism?

a) Entanglement

b) Coherence

c) Decoherence

d) Measurement

**Answer: ** Answer: b) Coherence

Which quantum gate is used to perform a controlled-phase shift?

a) Hadamard gate

b) Pauli-Z gate

c) CNOT gate

d) Toffoli gate

**Answer: ** Answer: b) Pauli-Z gate

Which principle states that the act of measuring a qubit does not disturb its superposition?

a) Pauli exclusion principle

b) Heisenberg uncertainty principle

c) Measurement principle

d) No-cloning theorem

**Answer: ** Answer: c) Measurement principle

Which type of quantum error correction code is obtained by concatenating multiple smaller codes?

a) Stabilizer codes

b) Topological codes

c) Concatenated codes

d) Surface codes

**Answer: ** Answer: c) Concatenated codes

a) Entanglement

b) Coherence

c) Decoherence

d) Measurement

**Answer: ** Answer: a) Entanglement

Which quantum algorithm is used for solving problems with a yes/no answer with a single query?

a) Grover’s algorithm

b) Shor’s algorithm

c) Quantum Fourier transform

d) Deutsch-Jozsa algorithm

**Answer: ** Answer: d) Deutsch-Jozsa algorithm

Which principle states that it is impossible to simultaneously know the precise values of complementary variables of a quantum system?

a) Pauli exclusion principle

b) Heisenberg uncertainty principle

c) Measurement principle

d) No-cloning theorem

**Answer: ** Answer: b) Heisenberg uncertainty principle

a) Entanglement

b) Coherence

c) Decoherence

d) Measurement

**Answer: ** Answer: a) Entanglement

Which quantum gate is used to perform a controlled-Hadamard operation?

a) Hadamard gate

b) Pauli-X gate

c) CNOT gate

d) Toffoli gate

**Answer: ** Answer: c) CNOT gate

Which principle states that the act of measuring a qubit collapses its superposition into a definite state?

a) Pauli exclusion principle

b) Heisenberg uncertainty principle

c) Measurement principle

d) No-cloning theorem

**Answer: ** Answer: c) Measurement principle

Which type of quantum error correction code is used to protect qubits from arbitrary errors?

a) Stabilizer codes

b) Topological codes

c) Concatenated codes

d) Surface codes

**Answer: ** Answer: a) Stabilizer codes

a) Entanglement

b) Coherence

c) Decoherence

d) Measurement

**Answer: ** Answer: a) Entanglement

Which quantum gate is used to create superposition?

a) Hadamard gate

b) Pauli-X gate

c) CNOT gate

d) Toffoli gate

**Answer: ** Answer: a) Hadamard gate

a) Entanglement

b) Coherence

c) Decoherence

d) Measurement

**Answer: ** Answer: a) Entanglement

Which quantum algorithm is used for searching an unsorted database with a quadratic speedup?

a) Grover’s algorithm

b) Shor’s algorithm

c) Quantum Fourier transform

d) Deutsch-Jozsa algorithm

**Answer: ** Answer: a) Grover’s algorithm

Which principle states that the more precisely the position of a particle is known, the less precisely its momentum can be known?

a) Pauli exclusion principle

b) Heisenberg uncertainty principle

c) Measurement principle

d) No-cloning theorem

**Answer: ** Answer: b) Heisenberg uncertainty principle

Which property of qubits is susceptible to environmental disturbances and leads to loss of quantum coherence?

a) Entanglement

b) Coherence

c) Decoherence

d) Measurement

**Answer: ** Answer: c) Decoherence

Which type of quantum gate is used to perform controlled-NOT operations?

a) Hadamard gate

b) Pauli-X gate

c) CNOT gate

d) Toffoli gate

**Answer: ** Answer: c) CNOT gate

Which principle states that the state of a quantum system remains constant during the unitary evolution?

a) Pauli exclusion principle

b) Heisenberg uncertainty principle

c) Measurement principle

d) Schrödinger’s equation

**Answer: ** Answer: d) Schrödinger’s equation

Which type of quantum error correction code is based on non-Abelian anyons?

a) Stabilizer codes

b) Topological codes

c) Concatenated codes

d) Surface codes

**Answer: ** Answer: b) Topological codes

Which property of qubits allows for the possibility of quantum parallelism?

a) Entanglement

b) Coherence

c) Decoherence

d) Measurement

**Answer: ** Answer: b) Coherence

Which quantum gate is used to perform a controlled-phase shift?

a) Hadamard gate

b) Pauli-Z gate

c) CNOT gate

d) Toffoli gate

**Answer: ** Answer: b) Pauli-Z gate

Which principle states that the act of measuring a qubit does not disturb its superposition?

a) Pauli exclusion principle

b) Heisenberg uncertainty principle

c) Measurement principle

d) No-cloning theorem

**Answer: ** Answer: c) Measurement principle

Which type of quantum error correction code is obtained by concatenating multiple smaller codes?

a) Stabilizer codes

b) Topological codes

c) Concatenated codes

d) Surface codes

**Answer: ** Answer: c) Concatenated codes

a) Entanglement

b) Coherence

c) Decoherence

d) Measurement

**Answer: ** Answer: a) Entanglement

Which quantum algorithm is used for solving problems with a yes/no answer with a single query?

a) Grover’s algorithm

b) Shor’s algorithm

c) Quantum Fourier transform

d) Deutsch-Jozsa algorithm

**Answer: ** Answer: d) Deutsch-Jozsa algorithm

Which principle states that it is impossible to simultaneously know the precise values of complementary variables of a quantum system?

a) Pauli exclusion principle

b) Heisenberg uncertainty principle

c) Measurement principle

d) No-cloning theorem

**Answer: ** Answer: b) Heisenberg uncertainty principle

a) Entanglement

b) Coherence

c) Decoherence

d) Measurement

**Answer: ** Answer: a) Entanglement

Which quantum gate is used to perform a controlled-Hadamard operation?

a) Hadamard gate

b) Pauli-X gate

c) CNOT gate

d) Toffoli gate

**Answer: ** Answer: c) CNOT gate