CHSE Odisha Elective Information Technology common mistakes
CHSE Odisha Elective Information Technology · Understand the traps and how to avoid them.
When asked to classify a device or component (input vs output, primary vs secondary storage, hardware vs software), the candidate answers from the device's everyday use rather than from where data enters or leaves the system, so a touchscreen is called input-only, a pen drive is called primary memory, and firmware is called hardware.
Classroom teaching often labels devices by familiar examples (keyboard, monitor) and candidates memorise the example list instead of the defining criterion: direction of data flow relative to the CPU, and volatility/access method for memory. Touchscreens and modems, which do both, break the memorised list.
What to do instead
Learn one test sentence per classification and apply it mechanically. Input: data moves from the outside world toward the CPU. Output: data moves from the CPU outward. For storage, ask two questions - does it lose contents on power-off (volatile = RAM) and is it directly addressed by the CPU (primary) or accessed through a controller (secondary). Practise on the awkward cases: touchscreen (both), modem (both), cache (primary, volatile), ROM (primary, non-volatile), SSD (secondary).
The candidate gives a one-line definition of an operating system ('software that runs the computer') and cannot then answer function-based questions - memory management, process scheduling, device management, file system, user interface - or distinguish a single-user single-task OS from a multi-user or real-time one.
OS topics are studied as a vocabulary list rather than as a set of jobs the OS performs, so when a question asks which function is being described, the candidate has no mapping from description to function name.
What to do instead
Build a five-function checklist (process/CPU management, memory management, file management, device/I-O management, security and user interface) and for each function write one concrete example of the OS doing it (e.g. deciding which ready process gets the CPU next = scheduling). Then classify OS types by two axes: number of users and number of tasks, plus special-purpose types (real-time, embedded, network).
File-management questions involving paths are answered by pattern-matching the visible text: the candidate cannot say whether C:\School\Notes\unit1.txt and C:\School\Unit1.txt are the same file, cannot state the parent folder of a given path, and mixes up absolute and relative paths and file extensions.
Candidates read paths as single strings rather than as a hierarchy separated by delimiters, and they have not internalised that Windows comparisons are case-insensitive while many other systems are case-sensitive.
What to do instead
Practise drawing the folder tree for a given path and reading it back: the last element is the file, the element before it is the immediate parent, the first element with the colon is the drive/root. Write out both the absolute path and a relative path from a stated current folder for the same file. Memorise the meaning of common extensions (.txt, .docx, .xlsx, .pptx, .html, .exe, .jpg) and what application opens each.
In word processing, the candidate applies formatting by selecting nothing and then changing the setting, or presses Enter repeatedly to push text down a page, and then cannot explain why a heading style, page break, or table of contents did not update. They also confuse character formatting with paragraph formatting.
The mental model is 'formatting is a property of the document' rather than 'formatting is a property of the selected text or the paragraph containing the cursor'. Manual spacing feels faster than learning styles and breaks, so it is what candidates actually practise.
What to do instead
Adopt two rules and state them in every answer: formatting applies to the current selection, or to the paragraph holding the cursor if nothing is selected. Use Enter only to end a paragraph; use a page break to start a new page and section breaks to change layout. Learn that heading styles feed the automatic table of contents, so restyling a heading updates it. Practise: bold one word, centre one paragraph, insert a page break, generate a contents page.
Spreadsheet questions are answered by reading the displayed value instead of the formula. The candidate cannot predict what =A1+$B$1 does when filled down, writes =A1+B1 where =SUM(A1:B1) was wanted, and reports a cell's contents as the number shown even when it is a formula result or an error such as #DIV/0! or #REF!.
Candidates interact with spreadsheets by clicking and looking, not by reading formulas, and relative versus absolute referencing is taught as syntax to memorise rather than as a rule about what changes when a formula is copied.
What to do instead
Train the copy rule out loud: on fill-down or fill-right, relative parts shift by the number of rows or columns moved, the $ locks a column, row, or both. For every practice sheet, click a calculated cell and write its formula before checking. Learn the standard error meanings: #DIV/0! division by zero, #REF! reference to a deleted cell, #NAME? unrecognised function name, #VALUE! wrong data type. Distinguish SUM, AVERAGE, COUNT, COUNTA, MAX, MIN, and IF with a worked example each.
Presentation and multimedia questions are answered with feature names only: the candidate cannot say when a slide transition differs from an object animation, what a slide master controls, why an embedded video plays on another computer while a linked one may not, and what resolution, frame rate, and file format mean for image and audio quality.
Presentation software is learned by producing one slideshow, so transitions, animations, masters, and linking are encountered incidentally and never separated conceptually.
What to do instead
Fix three distinctions in one sentence each: transition = effect between slides, animation = effect on an object within a slide, master = template controlling fonts, colours, and placeholders for all slides. For multimedia, learn that embedding stores a copy inside the file while linking stores a path, and that file size grows with resolution, frame rate, duration, and bit depth. Match formats to use: JPG for photographs, PNG for transparency, GIF for simple animation, MP3 for audio, MP4 for video.
Database answers blur the levels: the candidate calls a table a database, calls a row a field, cannot identify the primary key in a given table, and treats a foreign key as just another unique identifier rather than as a reference to another table's primary key. Normalisation and DBMS-versus-file questions are answered by guessing.
The terms are learned as a glossary without a worked example, so entity, attribute, record, and field never get anchored to a concrete table the candidate has built.
What to do instead
Use one small table throughout (Student: RollNo, Name, Class, City) and label every term against it: the table is a relation, RollNo is the primary key because it is unique and non-null, each row is a record, each column is a field. Then add a second table (Marks: RollNo, Subject, Score) and show that Marks.RollNo is a foreign key pointing to Student.RollNo. State the two normalisation goals plainly: no repeating groups, and no non-key column depending on only part of the key.
Networking questions are answered by naming devices without their layer or purpose: hub, switch, and router are used interchangeably, IP address and MAC address are confused, and the candidate cannot say what a subnet mask, DNS, or DHCP actually does. Topology and bandwidth-versus-latency questions are answered from the word's everyday feel.
Devices are memorised as a list of boxes rather than by the address they use and the scope they serve (one network versus between networks), and protocol names are learned without the problem each one solves.
What to do instead
Attach each device to a decision: hub repeats to all ports, switch forwards by MAC address within one network, router forwards by IP address between networks. Attach each protocol to a problem: DNS turns names into IP addresses, DHCP hands out IP configuration automatically, HTTP carries web pages. Learn that bandwidth is capacity (bits per second) while latency is delay (milliseconds) and they are independent. Draw one home network and label each device and address type.
HTML answers contain unclosed or wrongly nested tags, attributes written without quotes or with the wrong name (href used on an image, src used on a link), and the candidate cannot predict what a short page will display because they never separate structure from presentation. Lists, tables, and forms are the weakest areas.
Candidates copy fragments from examples without learning the tag's required attributes and nesting rules, and they read HTML as text to be reproduced rather than as a tree the browser parses.
What to do instead
Practise writing short pages by hand and checking them in a browser. Memorise the attribute pairs: , , , , . Learn the nesting rule that elements close in reverse order of opening. Build one page each for a nested list, a table with , and a form with text, radio, checkbox, and submit inputs, and state for each what the browser renders.
Programming and logic questions are answered by tracing code in the head and guessing the output. The candidate mishandles operator precedence, off-by-one loop bounds, and the difference between = (assignment) and == (comparison), and cannot convert a simple problem statement into an algorithm with a start, input, decision, and stop.
Code is read passively rather than executed step by step, and precedence and loop behaviour are assumed to follow ordinary reading order (left to right) rather than the language's rules.
What to do instead
Trace on paper with a variable table: one column per variable, one row per statement executed, writing values after each step. Apply precedence explicitly (brackets, then exponent, then multiply/divide, then add/subtract, then comparison, then logical NOT/AND/OR) and rewrite ambiguous expressions with brackets. For loops, write the first and last iteration values before predicting output. Practise converting three word problems into pseudocode with explicit input, processing, decision, and output steps.
Cyber-safety and ethics answers stay at slogan level ('use a strong password', 'don't share personal information') and cannot classify a described incident - phishing, pharming, ransomware, cyberstalking, plagiarism, software piracy - or name the concrete protective step and the reporting route for it. Emerging-technology questions are answered with buzzwords without a use case.
These topics are revised as a list of warnings rather than as scenarios to diagnose, so the candidate recognises the words but not the behaviour pattern that identifies the threat or the ethical violation.
What to do instead
Learn each threat by its signature behaviour: phishing arrives as a message urging urgent action and asking you to click or reveal credentials; pharming redirects you to a fake site without a lure message; ransomware denies access until payment; piracy is unauthorised copying of licensed software; plagiarism is presenting another's work as your own without attribution. Pair each with a defence (verify sender and URL, use multi-factor authentication, keep offline backups, use licensed or open-source software, cite sources) and a response (report to a teacher, parent, or platform; change compromised passwords). For emerging technologies, attach one concrete use and one risk to each: AI, cloud computing, IoT, blockchain, 5G.