# Quantum Computing Interview Questions and Answers – Set 1 This is the first in series of practice tests / interview questions and answers in relation to Quantum computing. It touches upon the basic concepts in relation to some of the following:

• Qubit
• Difference between a bit and Qubit
• Superposition of Qubit states
• Quantum entanglement

This practice test will prove to be useful for Quantum Computing beginners / interns / freshers.

### Revision Notes – Quantum Computing Fundamentals

• Quantum computing is different than classical computing. Problems which are suited for quantum computing should be considered for Quantum computing.
• A Qubit is a two-state quantum mechanical system;
• A Qubit can be in superposition of both the states at the same time.
• A Qubit is similar to bit in the way that the measurement of Qubit has two possible outcomes, usually 0 and 1
• A Qubit is different than bit in the way that a Qubit can be in a state which is a superposition of both 0 and 1
• The two states in which a qubit may be measured are known as basis states (basis vectors)
• In quantum mechanics, the Bloch sphere is a geometrical representation of the pure state space of a 2-level quantum system. The Bloch sphere is actually, geometrically, spherical in shape.
• A Quantum logic gate can operate on a Qubit.
• 8 Qubits = 1 Qubyte (Quantum Byte)
• A Qubit can be measured with quantum register
• A Qubit is different than bit due to following reasons:
• It can have superposition of states, e.g., can be in both states (usually 0 and 1) at the same time.
• Can be entangled with other Qubit
• In case of 2-qubit system, it is not possible to determine state of individual qubit in the system as the states of the two qubits are entangled

### Practice Test – Quantum Computing Fundamentals

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#### In case of 2-qubit system, it is possible to determine state of individual qubit in the system.

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Quantum Computing Interview Questions and Answers - Set 1
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