Odisha CHSE +2 Vocational Computer Technique common mistakes
Odisha CHSE +2 Vocational Computer Technique · Understand the traps and how to avoid them.
While converting a decimal fraction such as 0.2 to binary, the candidate writes 0.001 and stops, or simply leaves the fraction out because the repeated-division method 'only works for whole numbers'.
Classroom drills almost always use whole numbers, so the repeated-multiplication-by-2 step is never practised long enough to become automatic, and there is no habit of checking the answer back.
What to do instead
Treat the integer part and the fractional part as two separate jobs. For the fraction, multiply only by 2, record the carry (0 or 1), carry the new fractional part forward, and read the carries downward. Stop after the number of bits the question asks for and label the answer as approximate if the fraction never terminates. Verify by adding place values 1/2 + 1/4 + 1/8 and so on.
Saves work as 'my project' with no extension, or with characters like : ? * " < > | or several spaces, and later submits a file the examiner's machine cannot open or identify.
Windows hides known file extensions by default, so a name typed as report.docx quietly becomes report.docx.docx, and the Save dialog accepts almost anything without complaint.
What to do instead
Turn on 'File name extensions' in the View tab of File Explorer and check the real name in the title bar after saving. Use only letters, digits, underscore and hyphen. Choose the extension that matches the tool (.docx for a document, .xlsx for a sheet, .accdb or .odb for a database) and reopen the file through File > Open to confirm its type. In the practical exam, copy the exact file name given in the question paper character by character.
Presses Enter repeatedly to push a heading onto a new page, types dozens of spaces to centre a title, and leaves a train of empty paragraphs between sections.
The candidate has learned typing in a plain text box, where Enter and Space are the only layout tools; paragraph dialog boxes, tab stops and page breaks have never been opened, and formatting marks are hidden so the damage is invisible.
What to do instead
Use Ctrl+Enter for a page break, the Centre alignment button (or a centre tab stop) for a title, and Paragraph > Spacing Before/After instead of blank lines. Turn on formatting marks (the pilcrow button) so every empty paragraph is visible, delete them, and check that the layout survives a change of font size and page margins.
Types =B2/C2 to compute a percentage, where C2 holds the class total, then drags the fill handle down the column; the first row looks right but every following row gives a wrong value or #DIV/0!.
Cell references are relative by default, and the $ symbol is memorised as a definition rather than practised, so nothing in the first row signals that the divisor is silently shifting.
What to do instead
Write =B2/$C$2 so the total cell is locked, and press F4 while editing to cycle through C2, $C$2, C$2 and $C2. Know the meaning: $ before the column fixes the column, $ before the row fixes the row. After filling, click rows 2, 3 and 4 and read each formula in the formula bar; if the divisor changes, the reference is wrong.
Builds a table by typing field names in Design View and accepting every default, so no primary key is set, roll numbers are stored as Text and sort as 1, 10, 100, 2, and duplicate admission numbers are accepted without protest.
Design View is treated as a place to write captions rather than to define structure; Short Text is the default data type, and the candidate moves straight to Datasheet View to enter data before the structure is settled.
What to do instead
Design first, enter data second. Mark the unique field as Primary Key (it then refuses duplicates and blanks), set Number for marks, roll numbers and amounts, Date/Time for dates, and add a validation rule where the question implies a range. Test the design by deliberately entering a duplicate key and a non-numeric mark and confirming both are rejected.
Crams ten or twelve full sentences onto each slide in three different fonts, animates every object, and builds every slide from a blank layout with hand-placed text boxes instead of a title and content layout.
The slide is treated as a page of a report, with the assumption that more text means more marks; animation is fun to add, and the Slide Master is never opened, so consistency has to be done by hand each time.
What to do instead
Apply one idea per slide, no more than about six short lines of about six words each, with detail spoken rather than written. Choose one heading font and one body font, keep strong contrast, and put the repeated title style and logo into the Slide Master once. Use transitions sparingly and run the slideshow at full screen to check readability from the back of a room.
Writes 'please find the file attached' in the body, clicks Send without attaching anything, leaves the Subject blank, or pastes the whole message into the Subject line; also puts a large mailing list in Cc when addresses should be hidden.
Composition usually happens body-first and attachment-last, there is no final review step, and Cc versus Bcc is memorised as a definition without ever being used in a real send.
What to do instead
Attach first, then write the body, then check that the attachment appears as a named item before pressing Send. Give the Subject about six words that identify the content, and keep the message itself in the body with a greeting, one clear request and a sign-off. Use To for people who must act, Cc for people who only need to know (visible to all), and Bcc when recipients must not see each other's addresses.
Writes scanf("%d", num) without the ampersand, uses %d to read a float, or writes if (a = b) intending to compare two values.
The & looks optional because scanf on a character array does not need it, many compilers only warn rather than stop, and the single = is the equality sign learned in mathematics.
What to do instead
Memorise the rule: scanf needs the address of an ordinary variable, so &num for int and float, but a bare array name for %s. Match specifiers to declared types (%d int, %f float, %c char, %s string, %lf for double). For comparison always write ==, read it aloud as 'is equal to', and compile with all warnings enabled (for example -Wall) and read every warning before running.
Calls 192.168.0.5 a Class B address because 192 'looks large', gives 255.255.255.0 as the default mask of a Class A address, or states that a straight-through cable joins two PCs directly.
Address classes are memorised as a table of ranges without anchor numbers, so any address outside 10.x or 127.x is guessed; cable types are learned as vocabulary rather than by what each pin carries.
What to do instead
Anchor the boundaries: 1-126 is A, 128-191 is B, 192-223 is C, 224-239 is D, 240-255 is E, and 127 is reserved for loopback. Default masks are 255.0.0.0 (/8), 255.255.0.0 (/16) and 255.255.255.0 (/24). For cabling use the rule 'like devices need crossover, unlike devices need straight-through', so PC to switch is straight-through and PC to PC or switch to switch is crossover. Classify ten random addresses, then mark your own answers against the boundaries.
In the viva, the candidate cannot explain a single line of the program or query being demonstrated, cannot name the tables and fields used, and answers questions by reading aloud from the project synopsis.
The project was assembled once, possibly copied from a senior or a website, and never re-read or re-run; documentation and code were written at different times by different hands, and no rehearsal took place.
What to do instead
Keep a lab record written in your own words, with a comment on each block of code and a one-line purpose for each table, field and form. Be able to state input, processing and output for the project in one sentence each, and rehearse three questions: why this data type or structure, what happens if the user enters wrong data, and what you would add next. Run the project from a clean start a day before the viva and note any errors you fixed, because examiners often ask what problems you met.