Subject Knowledge (Concerned Teaching Subject)
Scope of the subject paper
The PGT subject paper is set at postgraduate level and tests depth in the concerned teaching subject, such as Physics, Chemistry, Mathematics, Biology, English, Hindi, History, Geography, Commerce, Economics or Computer Science. Items cover core theory, derivations, numericals, definitions, classification and applications. Treat NCERT Classes XI–XII as the floor and first-year university material as the ceiling, with questions that link chapters rather than test isolated facts.
What is actually tested
- Conceptual clarity: why a result holds, not just the formula.
- Numerical accuracy under time pressure: units, signs, significant figures.
- Precise terminology, exceptions and conditions of validity.
- Multi-step problems combining two or more sub-topics.
Worked example
Evaluate lim(x→0) sin 3x / tan 5x. Rewrite as (sin 3x)/(3x) × (5x)/(tan 5x) × (3/5). As x→0, sin3x/(3x)→1 and 5x/tan5x→1, so the limit is 3/5. L'Hôpital gives the same: (3 cos 3x)/(5 sec²5x) → 3/5 at x=0. Using standard limits avoids unnecessary differentiation and sign errors.
What costs marks
- Applying a formula outside its conditions, such as L'Hôpital to a non-0/0 form.
- Dropping the constant of integration or a negative sign in trigonometric derivatives.
- Misreading the command word: derive vs state vs calculate.
- Ignoring NCERT-level exceptions while over-relying on one reference book.