UPSC Prelims 2022 Q35: Science & Technology – Computer & Information Technology
Which one of the following is the context in which the term "qubit" is mentioned?
- (a) Cloud Services
- (b) Quantum Computing
- (c) Visible Light Communication Technologies
- (d) Wireless Communication Technologies
Answer: (b) Quantum Computing
Explanation
Qubit — the basic unit of quantum computing
| Feature | Classical bit | Qubit |
|---|---|---|
| States | 0 or 1 | 0, 1, or a superposition of both |
| Linking | Independent | Qubits can be entangled |
| Power | Grows linearly | Grows exponentially with each added qubit |
Key quantum ideas:
| Concept | Meaning |
|---|---|
| Superposition | A qubit holds many possibilities at once |
| Entanglement | The state of one qubit is linked to another, even at a distance |
| Decoherence | Qubits lose their quantum state easily — the main engineering problem |
India: the National Quantum Mission (2023) has an outlay of about ₹6,003 crore and aims for 50–1,000 qubit computers in 8 years.
Answer: (b) Quantum Computing.
Why each option is right or wrong
- (a) Incorrect. Cloud services use classical bits; a qubit is a quantum unit.
- (b) CORRECT. A qubit is the basic unit of quantum computing, using superposition and entanglement.
- (c) Incorrect. Visible Light Communication (Li-Fi) sends ordinary bits with light.
- (d) Incorrect. Wireless communication uses classical bits.
Key point
Qubit = quantum bit; superposition + entanglement; India's National Quantum Mission (2023) targets 50–1,000 qubits.
Remember
A qubit is the basic unit of quantum computing.
Common mistakes
- Thinking a qubit is just a faster bit; it can be in a superposition of 0 and 1.
- Confusing quantum computing with quantum communication (QKD).
- Forgetting India's National Quantum Mission approved in 2023.
Exam tip
'Q' in qubit = quantum. That alone settles the question.
Sources
- Department of Science and Technology — National Quantum Mission (2023)
- NCERT Class XII — Physics (Dual Nature of Radiation and Matter)