About Vectors in FSC Mathematics
Vectors is one of the 14 main chapters in our Federal Board FSC Mathematics question bank (11th and 12th class), and about 10% of its real questions come from it. Tayyari Karo has 46 real questions on this chapter from 2023 to 2026; 21 are multiple choice and marked instantly, and the rest are short and long questions with a model answer. By difficulty: 28 medium, 12 easy, 6 hard.
Work through the questions below, then open the explanation for each one. Redo the ones you missed a few days later.
Try 8 real questions
These are real past-paper questions. Think of your answer first, then open the explanation.
2026 Annual · 11th · Vectors
Scalar product of two non-zero vector is maximum when both vectors are:
- Parallel
- In opposite direction
- Mutually perpendicular
- At 45° to each other
Show answer and explanation
Answer: A. Parallel
a·b=|a||b|cosθ is maximum (=|a||b|) when θ=0 (parallel, same direction).
2026 Annual · 12th · Vectors
For the vector function r(t)=⟨ln(t−1),√(4−t)⟩, the domain in ℝ is:
- (1,4)
- [1,4)
- (1,4]
- [1,4]
Show answer and explanation
Answer: C. (1,4]
t−1>0 ⇒ t>1; 4−t≥0 ⇒ t≤4 ⇒ (1,4].
2025 1st Annual · 11th · Vectors
A force F→=2î+ĵ+3k̂ moves an object along a displacement vector d→=3î+4ĵ−2k̂. What is the work done?
- −4
- 10
- 4
- 16
Show answer and explanation
Answer: C. 4
W=F→·d→=6+4−6=4.
2025 2nd Annual · 11th · Vectors
For what value of x, vectors 2i−j+3k and xi+2j−2k are orthogonal (mutually perpendicular)?
- −2
- 1
- 2
- 4
Show answer and explanation
Answer: D. 4
Dot product 2x−2−6=0 ⇒ x=4.
2024 Annual · 11th · Vectors
What is the projection of a along b if a = 3i + j − k and b = i?
- 3
- 3/√11
- 3/√11
- (3/√11)i
Show answer and explanation
Answer: A. 3
Projection of a along b = (a·b)/|b| = [(3)(1)+(1)(0)+(−1)(0)] / 1 = 3.
2024 Annual · 12th · Vectors
What is the Cosine of the angle that a vector v=√2i+j+k makes with the y‑axis?
- 60°
- 45°
- 30°
- 90°
Show answer and explanation
Answer: A. 60°
|v|=√(2+1+1)=2. Cos(angle with y‑axis) = (component along j)/|v| = 1/2, so the angle is 60°.
2026 Annual · 11th · Vectors
A force F→=3î−2ĵ+k̂ acts at point (1,2,3). Find the moment about the origin.
Show model answer
M→ = r→×F→ where r→=(1,2,3)
= (2(1)−3(−2), −(1(1)−3(3)), 1(−2)−2(3)) = (2+6, −(1−9), −2−6)
M→ = 8î+8ĵ−8k̂
2025 2nd Annual · 11th · Vectors
If a→=5î−2ĵ+k̂ and b→=î+2ĵ+2k̂, then find projection of a→ along b→ and projection of b→ along a→.
Show model answer
a→·b→ = 5−4+2 = 3; |b→|=3; |a→|=√30
Projection of a→ along b→ = (a→·b→)/|b→| = 3/3 = 1
Projection of b→ along a→ = (a→·b→)/|a→| = 3/√30 = √30/10 ≈ 0.548