Complex Numbers Class 11 MCQs with Solutions (NCERT Based)
Complex Numbers Class 11 MCQs with Solutions
Class: 11 | Subject: Mathematics | Section: Algebra
Topic: Complex Numbers – NCERT Based Practice Questions
Aligned with CBSE Board Examination Standard
Topic: Complex Numbers – NCERT Based Practice Questions
Aligned with CBSE Board Examination Standard
Instructions: These Multiple Choice Questions (MCQs) are designed strictly as per the NCERT syllabus, making them ideal for CBSE Class 11 Board Examination practice. Each question includes a detailed concept‑clearing explanation.
1. The imaginary unit i is defined as:
Answer: B
Explanation: By definition, i = √−1.
Explanation: By definition, i = √−1.
2. i² equals:
Answer: B
Explanation: Squaring √−1 gives −1.
Explanation: Squaring √−1 gives −1.
3. Standard form of complex number:
Answer: B
Explanation: a = real part, b = imaginary part.
Explanation: a = real part, b = imaginary part.
4. Real part of 3+4i:
Answer: B
Explanation: Real coefficient is 3.
Explanation: Real coefficient is 3.
5. Imaginary part of 5−2i:
Answer: B
Explanation: Coefficient of i is −2.
Explanation: Coefficient of i is −2.
6. Conjugate of 3+4i:
Answer: A
Explanation: Change sign of imaginary part.
Explanation: Change sign of imaginary part.
7. i⁴ equals:
Answer: A
Explanation: i⁴=(i²)²=(−1)²=1.
Explanation: i⁴=(i²)²=(−1)²=1.
8. Modulus of 3+4i:
Answer: A
Explanation: √(3²+4²)=5.
Explanation: √(3²+4²)=5.
9. Argument represents:
Answer: B
Explanation: Angle with positive real axis.
Explanation: Angle with positive real axis.
10. (1+i)(1−i)=
Answer: C
Explanation: =1−i²=2.
Explanation: =1−i²=2.
11. Purely imaginary number:
Answer: B
Explanation: Real part zero.
Explanation: Real part zero.
12. Purely real number:
Answer: B
Explanation: Imaginary part zero.
Explanation: Imaginary part zero.
13. Addition of complex numbers follows:
Answer: B
Explanation: Add real & imaginary parts separately.
Explanation: Add real & imaginary parts separately.
14. Product of conjugates equals:
Answer: A
Explanation: a²+b² (purely real).
Explanation: a²+b² (purely real).
15. i⁶ equals:
Answer: A
Explanation: i⁶=i⁴·i²=1·(−1)=−1.
Explanation: i⁶=i⁴·i²=1·(−1)=−1.
16. Geometrically complex numbers are represented on:
Answer: B
Explanation: Real vs imaginary axes.
Explanation: Real vs imaginary axes.
17. Distance from origin equals:
Answer: B
Explanation: Magnitude of complex number.
Explanation: Magnitude of complex number.
18. If z=0+0i then modulus:
Answer: B
Explanation: Distance from origin zero.
Explanation: Distance from origin zero.
19. Reciprocal of i:
Answer: B
Explanation: 1/i = −i.
Explanation: 1/i = −i.
20. Equation x²+1=0 has roots:
Answer: B
Explanation: x²=−1 ⇒ x=±i.
Explanation: x²=−1 ⇒ x=±i.