NEB Class 11 • Computer Science • Programming Concepts • Concept Guide
BCD, ASCII & Unicode: NEB Class 11 Computer Guide
Master BCD, ASCII and Unicode through clear concepts, representations, a reliable answer method and exam-focused practice.

Concepts · Worked reasoning · NEB practice
Quick answer: BCD encodes each decimal digit separately in binary; ASCII maps a limited character set to numbers; Unicode assigns code points across writing systems and uses encodings such as UTF-8.
Core concept
What BCD, ASCII and Unicode means physically
BCD encodes each decimal digit separately in binary; ASCII maps a limited character set to numbers; Unicode assigns code points across writing systems and uses encodings such as UTF-8.
Keep value representation separate from character encoding: decimal 59 in BCD is 0101 1001, while character “5” has a character code.
The institutional reference gives the wider physical model; the CDC curriculum determines the NEB boundary.
Worked checkpoint with interpretation
UTF-8 represents ASCII characters in one byte but uses multiple bytes for many other Unicode code points, supporting Nepali text.
Do not stop at the number. State what the sign, ratio, spacing, frequency or direction means. A common error is Treating BCD as ordinary binary, equating Unicode with UTF-8, assuming one character always equals one byte, or confusing digits with numeric values.
NEB answer method
Model → evidence → equation → check
First identify the system and what the question asks. Label the diagram, apparatus or reaction with SI quantities, then state the principle before selecting an equation. Solve symbolically where possible and check units, limiting cases and chemical or physical meaning.
| Stage | Question | Evidence |
|---|---|---|
| Model | What is idealised? | Assumption stated |
| Representation | Which diagram fits? | Labels or balanced equation |
| Calculation | Which relation follows? | Symbols then SI values |
| Evaluation | Does it make sense? | Unit, sign and trend check |
Make the idea concrete in Nepal
Connect the model to a school laboratory, household technology, health, environment, energy or local material. The example should clarify the science rather than merely mention a place. Compare a prediction with an observation and record uncertainty.
Review the NEB Class 11 Computer Science revision roadmap and the complete Computer Science guide. For online or physical tuition, call 9846662070.
Questions students ask about BCD, ASCII and Unicode
What is the central idea of BCD, ASCII and Unicode?
BCD encodes each decimal digit separately in binary; ASCII maps a limited character set to numbers; Unicode assigns code points across writing systems and uses encodings such as UTF-8.
Which equation should I remember?
Keep value representation separate from character encoding: decimal 59 in BCD is 0101 1001, while character “5” has a character code.
How should I begin a numerical?
Draw the situation, list known quantities in SI units, choose the governing relation symbolically, substitute once and finish with a unit and reasonableness check.
What is a common exam mistake?
Treating BCD as ordinary binary, equating Unicode with UTF-8, assuming one character always equals one byte, or confusing digits with numeric values.
How can I practise this topic?
Alternate one concept explanation, one diagram and two numericals. Revisit errors after a day instead of only rereading the solution.
Where can I get tuition support?
For online or physical KTM Tuition classes, call 9846662070. After Grade 12, the MKS Education panel below gives preparation and pre-counselling contacts.
Frequently asked questions
References and next steps
Scope checked against CDC Nepal; concept support from an institutional reference and OpenStax Science. Continue with the BCD, ASCII and Unicode cluster.
NEB +2 tuition support
Ask about online or physical tuition
For focused Class 11 and Class 12 subject tuition, lesson clarification, worked-example practice and exam preparation, call 9846662070. Class mode, timetable, teacher availability and fees should be confirmed directly before enrolment.
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