Chapter 4: Sequences and Series – MCQs Test (Class 11, Federal Board)

This MCQs test is designed to help Class 11 students grasp the core concepts of Sequences and Series from the National Book Foundation syllabus (Federal Board). It covers arithmetic and geometric sequences, sum formulas, infinite series, and real-world applications—all essential topics for your board exams!

Chapter 4: Sequence and Series | National Book Foundation

June 20, 2025

1. 
If $a,b$ are negative and G.M is also negative

2. 
The reciprocal of the term of H.P is.....

3. 
If $a,b,c$ are in A.P, then $3^{a},3^{b},3^{c}$ are in:

4. 
If $\frac{1}{a},\frac{1}{b}$ and $\frac{1}{c}$ are in A.P then b is equal to_________.

5. 
If $y=\frac{2}{3}x+\frac{4}{9}x^2+\frac{8}{27}x^3+....$ then interval of convergence is____

6. 
The arithmetic mean in the sequence $-7$,_,_,$5$ are

7. 
What is sum of n term with nth term $a_{n} = 4n+1$

8. 
$\sum_{k=1}^{3} k^2$ is equal to:

9. 
$a_{5}$ in G.P $3,6,12,...$ will be _____

10. 
If $\frac{1}{5}, \frac{1}{8}$ are two H.M between $\frac{1}{2}$ and $b$ then be equals to

11. 
The series $1+\frac{x}{2}+\frac{x^2}{4}+...$ is convergent if________

12. 
If $\frac{1}{a},\frac{1}{b}$ and $\frac{1}{c}$ are in G.P then common ratio is equal to_________

13. 
$S_{n}=1+2+3+...+n$ can also be shown as_______

14. 
The nth term of sequence $\frac{1}{3},\frac{2}{5},\frac{3}{7},....$ is:

15. 
$\sum_{k=1}^{n} 5$ is equal to:

16. 
Sequence is denoted by______

17. 
$\sum_{k=1}^{n} k=?$ or (sum of first n terms)

18. 
$\sum_{k=1}^{n} k^{3}=?$ or $(1^3+2^3+3^3+...+n^3)=?$

19. 
An infinite geometric series is convergent if _____

20. 
If $a_{n}-a_{n-1}=n+2$, $a_{1}=2$ then $a_{3}=?$

21. 
If $a_{1}$ and $r$ are the first term and common ratio respectively then the $(n+1)^{th}$ term of G.P is________

22. 
If $a,A,b$ are in A.P then $2A=?$

23. 
If the nth term of an A.P is $\frac{1}{2}(3-n)$ then first three terms are _________

24. 
If $\frac{4}{7}$ be the third term of H.P, then third term of A.P is:

25. 
The sigma notation for the sum $-2+4-6+8$ is:

26. 
The formula $S_{n}=\frac{a(r^{n}-1)}{r-1}$ is used for sum of a terms of G.P. if ____

27. 
Geometric mean of Two positive numbers a and b

28. 
What is the sum of infinite G.P; $2,\sqrt{2},1,...?$

29. 
If $x,y,z$ are in H.P. Sequence then value of z is ______

30. 
$a_{n}=\frac{(-1)^{n+1}}{2^{n}}$, then $a_{6}=?$

31. 
An arithmetic progression has a first term 12 and a fifth term 18, then the sum of first 25 term is.

32. 
For an infinite geometric series for which $|r|

33. 
If $a,b,c$ are in G.P and $a>0,b>0,c>0,$ then the reciprocals of $a,b,c$ form ______

34. 
An infinite sequence has no __________

35. 
Find first term of the geometric series, when $S_{n}=30,n=4,r=-2$

36. 
The sum $\sum_{r=2}^{\infty} \frac{1}{r^2-1}$ represents:

37. 
Which term of $64,60,56,52,...$ is zero?

38. 
G.Ms between $1$ and $\frac{1}{3}$ is:

39. 
Let $a,b$ be two positive numbers, where $a>b$ and $4\times\,G.M=5\times\,H.M$ for the numbers, the a is:

40. 
If A,G,H have their usual meanings and 'a' and 'b' are positive distinct real numbers and $G>0$, then:

41. 
The general term of the given series $\frac{1}{1.3}+\frac{1}{2.5}+\frac{1}{3.7}+...$ is

42. 
$\frac{1}{k}, \frac{1}{2k+1}, \frac{1}{4k-1}$ are in H.P then $k=?$

43. 
$\sum_{j=1}^{10} \sum_{i=1}^{15} k =?$

44. 
Arithmetic Mean between two numbers $\frac{1}{a}$ and $\frac{1}{b}$ is:

45. 
If $a_{n-2}=3n-11$ then nth term is

46. 
How many terms of sequence $18,15,12,....$ are needed to give a sum of 63?

47. 
Find the $26^{th}$ terms from the end of A.P : $2,7,12,17,...,222.$

48. 
$\sum_{k=1}^{n} k^{2}=?$ or $(1^2+2^2+3^2+...+n^2)=?$

49. 
Arithmetic mean between $2+\sqrt{2}$ and $2-\sqrt{2}$ is:

50. 
Sum of the series $1+3+5+7+9+11+...+n$ terms is:

51. 
The nth term of an A.P with usual notions is ______

52. 
$\sum_{k=1}^{n} 1=?$

53. 
An arithmetic series $S_{n}$ equals to ____

54. 
The next term of G.P. $1,2,4,8,16,...$ is:

55. 
In geometric sequence nth term equal to

56. 
If $\frac{1}{a},\frac{1}{b}$ and $\frac{1}{c}$ are in A.P then common difference is equal to_________.

57. 
For what value of $n$, $\frac{a^n+b^n}{a^{n-1}+b^{n-1}}$ is the A.M between a and b?

58. 
Sum of the series $\frac{5}{(13)^{1}}+\frac{55}{(13)^{2}}+\frac{555}{(13)^{3}}+\frac{5555}{(13)^{4}}+...$ up to $\infty$ is:

59. 
The A.M between two numbers a and b is ________

60. 
$0.1+0.01+0.001+0.0001+....$ the sum is:

61. 
$\sum_{k=1}^{10} 3=?$

62. 
Predict the general term for the sequence $\frac{4}{3},\frac{4}{9},\frac{4}{27},\frac{4}{81},...$

63. 
A.M between $\frac{a}{2}$ and $\frac{2}{a}$ is

64. 
A sequence $a_{n}$ is an arithmetic sequence if $\forall \, n\in\,\mathbb{N}$ and $n>1$:

65. 
The $(n+1)th$ term of an A.P is _______

66. 
In $\frac{1}{4.7}+\frac{1}{7.10}+\frac{1}{10.13}+$...., then $n^{th}$ term is:

67. 
Sum of $n$ arithmetic means between a and b is ________

68. 
Sum of $n$ terms of an A.P is ____

69. 
The $10^{th}$ term of $\frac{1}{2},\frac{1}{5},\frac{1}{8},...,$ is:

70. 
In the sequence $1,2,2,3,3,3,4,4,4,4,...$ where n-consecutive terms have the value n, the $22^{nd}$ term is:

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