What is the main function of the electronic spread sheet?

The correct answer is A, the national cloud computing initiative. MeghRaj is the name given to the Government of India Cloud, usually shortened to GI Cloud, under which government departments obtain their computing and storage from a common set of government managed data centres rather than each building its own. The aim is to cut duplicated hardware, shorten the time taken to launch an e-governance application and let departments pay only for what they use, and the name itself joins the Hindi word for cloud to the idea of governance. Option B is wrong because India's weather satellites belong to the INSAT series and the observation work is done by the India Meteorological Department, not by a cloud programme. Option C is wrong because rural connectivity is the business of the BharatNet optical fibre programme. Option D is wrong because digital payments run on the Unified Payments Interface and related systems built by the National Payments Corporation of India. Learn MeghRaj together with the three service models, since a question often pairs them.

The correct answer is A. The three terms sit one inside the other like circles. Artificial intelligence is the whole field of making machines behave intelligently, and it includes approaches that use no learning at all, such as rule based expert systems and search algorithms. Machine learning is the part of it in which the program is shown examples and works out the pattern itself instead of being given the rules. Deep learning is a part of machine learning that uses artificial neural networks with many hidden layers, and it is what made image recognition, speech recognition and machine translation work well. Option B is wrong because it inverts the outermost relation; artificial intelligence is the widest of the three, not the narrowest. Option C is wrong because it inverts the inner relation: deep learning is inside machine learning, not the other way round. Option D is wrong because the three are nested and not identical, and examiners test exactly this nesting. The three families of machine learning are supervised, unsupervised and reinforcement learning.

The correct answer is C, a qubit. A classical computer stores information in bits, each of which must be either zero or one at a given moment. A quantum computer uses a quantum bit, shortened to qubit, which can be in a superposition of zero and one at the same time, and qubits can also be entangled so that the state of one is tied to the state of another. These two properties allow a quantum machine to explore many possibilities together, which is why certain problems in factorisation, search and molecular simulation could be solved far faster than on any classical machine. Option A is wrong because the bit is the unit of classical computing, the very thing the qubit replaces. Option B is wrong because a byte is simply a group of eight bits, the usual unit for measuring storage. Option D is wrong because a nibble is a group of four bits, that is half a byte. Remember the trio of terms that come with the qubit: superposition, entanglement and decoherence, the last being the loss of the quantum state through disturbance.

The correct answer is A. Entries on a blockchain are grouped into blocks, and every block carries the cryptographic hash, a short fixed length fingerprint, of the block immediately before it. Changing even one character inside an old block changes that block's hash, which no longer matches the value recorded in the next block, and so the mismatch cascades through every later block; since identical copies of the chain are held by many computers on the network, the tampered copy is rejected at once. This is why a blockchain is called tamper evident and append only. Option B is wrong because it states the opposite of the design: a blockchain is deliberately distributed across many nodes and has no single server to attack. Option C is wrong because a password controls who may write, not whether a written record can be silently changed. Option D is wrong because fingerprints are a means of authenticating a person and are not used to seal blocks. The idea was published in the 2008 Bitcoin paper under the name Satoshi Nakamoto.

The correct answer is A, Radio Frequency Identification. An RFID system has a tag carrying a tiny chip and an antenna, and a reader that sends out radio waves; the tag answers with its stored identity, so an object can be recognised without being seen or touched and without a line of sight, unlike a barcode that must be shown to a scanner. Passive tags carry no battery and draw their power from the reader's signal, which is why they can be made as thin as a label. RFID is used in toll collection, library books, baggage handling, warehouse stock and animal identification, and it was work on exactly such tags that led Kevin Ashton to the phrase Internet of Things. Option B, option C and option D are all invented expansions that do not correspond to any real technology; they are offered only because they use the same letters. Note the related short range technology NFC, near field communication, which is the basis of tap to pay cards.