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

#### Quantum computing is _________ than classical computing

Correct!
Wrong!

#### A Qubit is a _________ quantum mechanical system.

Correct!
Wrong!

#### A Qubit can be in __________ of both the states at the same time

Correct!
Wrong!

#### Unlike a bit, the measurement of Qubit can have more than two possible outcomes

Correct!
Wrong!

#### Unlike a bit, the Qubit can be in both 0 and 1 state (superposition of both 0 and 1 states)

Correct!
Wrong!

#### The two states in which a qubit may be measured are known as ________

Correct!
Wrong!

#### Which of the following shape can be used to the pure state space of a 2-level quantum system?

Correct!
Wrong!

#### Which of the following can operate on a Qubit?

Correct!
Wrong!

#### 8 _______ is to 1 ______ as 8 _______ is to 1 ________

Correct!
Wrong!

#### The amount of information stored in N Qubits is ________ to the power of N classical bits

Correct!
Wrong!

#### A Qubit can be used to represent any ________ system

Correct!
Wrong!

#### A Qubit can be measured with __________ register.

Correct!
Wrong!

#### Which of the following makes Qubit different than a classical bit?

Correct!
Wrong!

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

Correct!
Wrong!

Quantum Computing Interview Questions and Answers - Set 1

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### References

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