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

September 29, 2025

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

2. 
Sequence is denoted by______

3. 
For what value of $n$, $\frac{a^n+b^n}{a^{n-1}+b^{n-1}}$ is the A.M between a and b?

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

5. 
$a_{n}=\frac{(-1)^{n+1}}{2^{n}}$, then $a_{6}=?$

6. 
The $10^{th}$ term of $\frac{1}{2},\frac{1}{5},\frac{1}{8},...,$ is:

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

8. 
An arithmetic progression has a first term 12 and a fifth term 18, then the sum of first 25 term is.

9. 
The A.M between two numbers a and b is ________

10. 
A sequence $a_{n}$ is an arithmetic sequence if $\forall \, n\in\,\mathbb{N}$ and $n>1$:

11. 
Find the $26^{th}$ terms from the end of A.P : $2,7,12,17,...,222.$

12. 
The next term of G.P. $1,2,4,8,16,...$ is:

13. 
$\frac{1}{k}, \frac{1}{2k+1}, \frac{1}{4k-1}$ are in H.P then $k=?$

14. 
$\sum_{j=1}^{10} \sum_{i=1}^{15} k =?$

15. 
Predict the general term for the sequence $\frac{4}{3},\frac{4}{9},\frac{4}{27},\frac{4}{81},...$

16. 
If A,G,H have their usual meanings and 'a' and 'b' are positive distinct real numbers and $G>0$, then:

17. 
For an infinite geometric series for which $|r|

18. 
G.Ms between $1$ and $\frac{1}{3}$ is:

19. 
An infinite sequence has no __________

20. 
$\sum_{k=1}^{10} 3=?$

21. 
$\sum_{k=1}^{n} k^{2}=?$ or $(1^2+2^2+3^2+...+n^2)=?$

22. 
An arithmetic series $S_{n}$ equals to ____

23. 
Sum of the series $\frac{5}{(13)^{1}}+\frac{55}{(13)^{2}}+\frac{555}{(13)^{3}}+\frac{5555}{(13)^{4}}+...$ up to $\infty$ is:

24. 
If $y=\frac{2}{3}x+\frac{4}{9}x^2+\frac{8}{27}x^3+....$ then interval of convergence is____

25. 
If $\frac{1}{a},\frac{1}{b}$ and $\frac{1}{c}$ are in A.P then b is equal to_________.

26. 
$\sum_{k=1}^{n} 5$ is equal to:

27. 
In $\frac{1}{4.7}+\frac{1}{7.10}+\frac{1}{10.13}+$...., then $n^{th}$ term is:

28. 
The sum $\sum_{r=2}^{\infty} \frac{1}{r^2-1}$ represents:

29. 
$0.1+0.01+0.001+0.0001+....$ the sum is:

30. 
How many terms of sequence $18,15,12,....$ are needed to give a sum of 63?

31. 
Sum of $n$ arithmetic means between a and b is ________

32. 
Which term of $64,60,56,52,...$ is zero?

33. 
Sum of $n$ terms of an A.P is ____

34. 
The nth term of an A.P with usual notions is ______

35. 
$\sum_{k=1}^{3} k^2$ is equal to:

36. 
If $a,b,c$ are in A.P, then $3^{a},3^{b},3^{c}$ are in:

37. 
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:

38. 
$a_{5}$ in G.P $3,6,12,...$ will be _____

39. 
If $a,b$ are negative and G.M is also negative

40. 
Geometric mean of Two positive numbers a and b

41. 
The $(n+1)th$ term of an A.P is _______

42. 
If the nth term of an A.P is $\frac{1}{2}(3-n)$ then first three terms are _________

43. 
$\sum_{k=1}^{n} k^{3}=?$ or $(1^3+2^3+3^3+...+n^3)=?$

44. 
If $\frac{1}{a},\frac{1}{b}$ and $\frac{1}{c}$ are in A.P then common difference is equal to_________.

45. 
$\sum_{k=1}^{n} 1=?$

46. 
The sigma notation for the sum $-2+4-6+8$ is:

47. 
If $a_{n}-a_{n-1}=n+2$, $a_{1}=2$ then $a_{3}=?$

48. 
Find first term of the geometric series, when $S_{n}=30,n=4,r=-2$

49. 
What is the sum of infinite G.P; $2,\sqrt{2},1,...?$

50. 
In geometric sequence nth term equal to

51. 
An infinite geometric series is convergent if _____

52. 
If $\frac{1}{5}, \frac{1}{8}$ are two H.M between $\frac{1}{2}$ and $b$ then be equals to

53. 
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:

54. 
$S_{n}=1+2+3+...+n$ can also be shown as_______

55. 
The arithmetic mean in the sequence $-7$,_,_,$5$ are

56. 
If $x,y,z$ are in H.P. Sequence then value of z is ______

57. 
If $\frac{4}{7}$ be the third term of H.P, then third term of A.P is:

58. 
If $a,b,c$ are in G.P and $a>0,b>0,c>0,$ then the reciprocals of $a,b,c$ form ______

59. 
Arithmetic Mean between two numbers $\frac{1}{a}$ and $\frac{1}{b}$ is:

60. 
Sum of the series $1+3+5+7+9+11+...+n$ terms is:

61. 
The reciprocal of the term of H.P is.....

62. 
If $a_{n-2}=3n-11$ then nth term is

63. 
If $\frac{1}{a},\frac{1}{b}$ and $\frac{1}{c}$ are in G.P then common ratio is equal to_________

64. 
If $a,A,b$ are in A.P then $2A=?$

65. 
$\sum_{k=1}^{n} k=?$ or (sum of first n terms)

66. 
The general term of the given series $\frac{1}{1.3}+\frac{1}{2.5}+\frac{1}{3.7}+...$ is

67. 
A.M between $\frac{a}{2}$ and $\frac{2}{a}$ is

68. 
Arithmetic mean between $2+\sqrt{2}$ and $2-\sqrt{2}$ is:

69. 
The formula $S_{n}=\frac{a(r^{n}-1)}{r-1}$ is used for sum of a terms of G.P. if ____

70. 
The series $1+\frac{x}{2}+\frac{x^2}{4}+...$ is convergent if________

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