What is the 2's complement of the binary number 101110?

The correct answer is D, Both I and II. The Post Office Protocol, best known in its third version POP3, lets a mail client download messages from a mail server, and it works in two modes. In the delete mode the message is removed from the server once it has been downloaded, which suits a person who always reads mail on the same computer. In the keep mode a copy stays on the server after downloading, so the same mail can be read again from another device. POP3 uses port 110, or port 995 when secured with SSL. Option A is wrong because both modes do exist in POP. Option B is wrong because keep mode is not the only one; delete mode is the default in many clients. Option C is wrong because delete mode is not the only one either. Exam tip: POP3 downloads mail and offers delete and keep modes, IMAP keeps mail on the server and syncs it across devices, and SMTP is the protocol that sends mail.

The correct answer is A, .tmp. A file with the .tmp extension is a temporary file, created by a program while it is working and normally deleted once the work is done. Word processors, browsers and installers make them to hold data they may need for recovery, and Windows keeps many of them in the Temp folder, which can be cleared safely. Option B is wrong because .txt is a plain text file that stores unformatted text and opens in Notepad. Option C is wrong because .tnt is not a standard file extension at all. Option D is wrong because .tar is an archive format from Unix that bundles many files into one, often compressed further as .tar.gz. Questions on extensions come up in every shift, so learn the common ones: .docx for Word, .xlsx for Excel, .pptx for PowerPoint, .exe for a program and .bak for a backup. Exam tip: .tmp is temporary, .bak is a backup and .tar is an archive.

The correct answer is D, Ministry of Education. The National Digital Library of India is a single window that brings together lakhs of learning resources, from school books to research papers, and lets a student search them free of cost in many Indian languages. It is developed by IIT Kharagpur under the National Mission on Education through Information and Communication Technology, a mission of the Ministry of Education; the ministry was called the Ministry of Human Resource Development when the library was launched and was renamed in 2020. Option A is wrong because the Ministry of Finance handles the budget, taxes and public spending, not education platforms. Option B is wrong because India has no ministry of that name; Science and Technology is a separate ministry of its own. Option C is wrong because the electronics and information technology ministry runs Digital India, e-governance services and BharatNet, but not this library. Exam tip: National Digital Library of India means IIT Kharagpur, the NMEICT mission and the Ministry of Education.

The correct answer is D, 50097. Hexadecimal is base sixteen, so the four places of C3B1 carry the weights 4096, 256, 16 and 1 from left to right, and the letters stand for numbers: A is 10, B is 11, C is 12, D is 13, E is 14 and F is 15. Putting the digits in place gives 12 into 4096, which is 49152, plus 3 into 256, which is 768, plus 11 into 16, which is 176, plus 1, and the four terms add up to 50097. Options A and B are far too small, because any four-digit hexadecimal number beginning with C is at least 12 into 4096, that is 49152, so 12197 and 32097 cannot be right. Option C lies in the right range but would need the second digit to be about 11, not 3, since 52097 minus 49152 is 2945, which is about 11 sixteens of 256. Exam tip: fix the weights 4096, 256, 16 and 1 in mind, and remember A to F mean 10 to 15.

The correct answer is D, Toggle Keys. A toggle key switches a feature on with one press and off with the next, so it has two states and keeps whichever one you left it in. Caps Lock, Num Lock, Scroll Lock and the Insert key work this way, and most keyboards carry a small indicator light that glows while the feature is on. Caps Lock, for instance, holds capital letters until it is pressed a second time. Option A is wrong because navigation keys move the cursor or the view: the four arrow keys with Home, End, Page Up and Page Down. Option B is not a standard class; keys such as Enter, Esc, Tab and the Windows key are grouped as control or special keys, and none of them stay switched on. Option C is wrong because the function keys are F1 to F12, which run one command each time they are pressed. Exam tip: the four toggle keys are Caps Lock, Num Lock, Scroll Lock and Insert.