Explore topic-wise InterviewSolutions in Current Affairs.

This section includes 7 InterviewSolutions, each offering curated multiple-choice questions to sharpen your Current Affairs knowledge and support exam preparation. Choose a topic below to get started.

1.

Show that the line through the points (1,-1,2), (3,4,-2) is perpendicular to the line through the points (0,3,2) and (3,5,6).

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Answer :The direction ratios of the two lines are 3-1, 4+1, -2-2 i.e., 2, 5, -4 and 3-0, 5-3, 6-2 i.e., 3, 2, 4 respectively.
The direction ratios of the line through `(x_1, y_1,z_1)` and `(x_2,y_2,z_2)` are `x_2-x_1, y_2-y_1, z_2-z_1`
`THEREFORE` The sum of products of the direction ratios = `2xx3+5xx2+(-4)xx4 = 6+10-16 = 0 `
HENCE, the two lines are perpendicular.
2.

Find the points of local maxima and local minima for the following functions. Also find respective maximum and minimum values. (i) y=x^(4)-14x^(2)+24x-3 (ii) y=((x+1)(x+4))/((x-1)(x-4)) (iii) y=x (x-1)^(2) (x+1)^(2) (iv) y=(log x)//x y=e^(x) sin x" in "[-pi,pi] y=sin x+cos x" in "[0,2pi]

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Answer :(i) max (1,8 ), min (-3 ,-120) and (2,5)
(i) max : (2,-9) and min (-2,-1/9)
(iii) `max (1/SQRT5): (16sqrt5)/(125) and (-1,0): " min "(-1)/sqrt5, -(16sqrt5)/(125), (1,0)`
(iv) `max (E 1/e) `
v `max ((3pi)/(4), (1)/sqrt2 e^(3pi//4)) min ((-pi)/(4), (-1)/(sqrt2), e^(-pi//4))`
3.

Solve the following linear programming problem graphically: Minimise Z=200x+500y……………1 subject to the constraints: x+2yge10……………2 3x+4yle24……………3 xge0,yge0…………..4

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ANSWER :(30,0)
4.

{:("Column A","", "Column B"),("The perimeter of quadrilateral",,"The The circumference of the circle"):}

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If column A is larger
If column B is larger
If the columns are EQUAL
If there is not ENOUGH INFORMATION to decide

Answer :B
5.

An aqueous ..............

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Solution :Borax is not any redox agent, not a bleach. Its aqueous solution turns red litmus BLUE & it can be titrated by titrating against `HCL`.
`Na_(2)B_(4)O_(7). 10H_(2)O+HCl RARR 2NACl+4H_(3) BO_(3)+4H_(2)O`
6.

By using the properties of definite integrals, evaluate the integrals int_(0)^(4)abs(x-1)dx

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ANSWER :5
7.

Construct truth tables for the following and indicate which of these are tautologiesp vv q rarr ~~(p^^q)

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SOLUTION :
8.

If 1,alpha_1,alpha_2,…..alpha_(n-1) are the n^(th) roots of unity and n is an odd natural number then(1+alpha_1)(1+alpha_2)…..(1+alpha_(n-1))=

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1
-1
0
-2

Answer :A
9.

Two coins are tossed . The probability of getting 2 tails if it is known that there is atleast one tail on the coins is

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`(1)/(3)`
`(2)/(3)`
`(1)/(4)`
`(1)/(5)`

Answer :A
10.

If the vectors of a trianlge are A(hati+hatj+2hatk), B(3hati-hatj+2hati) and C(2hati-hatj+hatk) the area of triangle is

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`2sqrt3` SQ UNITS
`sqrt3` sq units
`2sqrt3` sq units
3 sq units

Solution :Now , `AB=(3hat(i)-hat(j)+2HAT(k))-(hat(i)+hat(j)+2hat(k))=2hat(i)-2hat(j)`
and `AC=(2hat(i)-hat(j)+hat(k))-(hat(i)+hat(j)+2hat(k))=hat(i)-2hat(j)-hat(k)`
`(ABxxAC)=|{:(hat(i),hat(j),hat(k)),(2,-2,0),(1,-2,-1):}|`
`=hat(i)(2-0)-hat(j)(-2-0)+hat(k)(-4+2)`
`=2hat(i)+2hat(j)+2hat(k)`
`therefore` Area of TRIANGLE `AB=(1)/(2)|ABxxAC|`
`=(1)/(2)sqrt((2)^2+(2)^2+(-2)^2)`
`=(2)/(2)sqrt(1+1+1)=sqrt(3)` sq units.
11.

int (6x^(2) - 17 x - 5)/((x - 3)(x - 2)^(2))dx =

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`LOG"" ((X-2)^(2))/((x - 3)^(4)) + (3)/(x - 2)+ C `
`log ( x - 2)^(4) (x - 3)^(2) + (3)/(x -2)+ c `
`log ""((x - 2)^(8))/((x - 3)^(2)) - (15)/(x - 2) + c `
`log (x + 3) - (1)/(x -2)` +c

Answer :C
12.

Examine the continuity of the following function at the indicated pionts. f(x)={{:(,(x-cos (sin^(-1)x))/(1-tan(sin^(-1)x))x ne 1/2),(,(-1)/(sqrt2)x =1/sqrt2):}" at x="1/sqrt2

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ANSWER :CONTINUOUS
13.

If x=cos alpha+i sin alpha,y=cos beta+isinbeta, then (x-y)/(x+y)=

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`i.cos((alpha-beta)/(2))`
`i.sin((alpha-beta)/(2))`
`i.cot((alpha-beta)/(2))`
`i.tan((alpha-beta)/(2))`

ANSWER :D
14.

Choose the correct answer. Area of the region bounded by the curvey^2=4x, y-axis and the line y=3 is :

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2
`9/4`
`9/3`
`9/2`

ANSWER :B
15.

int (dx)/(x^(1//5)(1 +x^(4//5))^(1//2)) =

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`sqrt(1 + x^(4//5)) ` + c
`(5)/(2) sqrt(1 + x^(4//5))` + c
`x^(4//5) sqrt(1 + x^(4//5)) + c`
`(2)/(3) sqrt(1 + x^(4//5))` + c

Answer :B
16.

Does the function f(x) =3x^(2)-1 satisfy the condition of the Fermat theorem in the interval [(1,2)] ?

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ANSWER :YES
17.

If intsqrt(2)(sqrt(1+sinx)dx=4cos(ax+b)+c, then the value of a,b are

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`(1)/(2),(pi)/(4)`
`1,(pi)/(2)`
1,1`
none of these

Solution :LET `l=intsqrt(2)SQRT(1+sinx)dx`
`=sqrt(2)int("sin"(x)/(2)+"COS"(x)/(2))dx`
`{because+-sqrt(1+sinA)=sin((A)/(2))+cos((A)/(2))]`
`=2intsin((pi)/(4)+(x)/(2))dx`
`=-4cos((x)/(2)+(pi)/(4))+C`
But `l=-4cos(ax+b)+c`
On comparing, we get
`a=(1)/(2),b=(pi)/(4)`.
18.

Human being forms two sets of teeth during life, a set of _____teeth replaced by a set of _____teeth. Correct options in the blanks are -

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MILKY , Deciduous
Permanent , Milky
Deciduous , Adult
Temporary , Milky

Answer :A
19.

Point of contact of y=1-x w.r.t. y^(2)-y+x=0 is

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(1,1)
`((1)/(2),(1)/(2))`
(0,1)
(1,0)

ANSWER :C
20.

Let f: [0,1] to R be such that f(xy). F(y) AA x, y in (0,1) and f(0) != 0. If y = y(x) satisfies the differential equation, (dy)/(dx) = f(x) with y(9) = 1 they y((1)/(5))+y((4)/(5)) is equal to:

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4
3
5
2

Solution :`F(xy) = f(x).f(y)`
`f(o) = 1 as f(o) != 0 implies f(x) =1`
`(DY)/(DX) = f(x) = 1 implies y = x + C`
At `x = 0, y = 1 implies c = 1 implies y = x +1`
`implies y((1)/(5)) + y((4)/(5)) = 1/5 + 1 + 4/5 + 1 = (1+1+1) = 3`.
21.

X and Y are independent binomial variables. B(5,(1)/(2))and B(7,(1)/(2)) then P(X + Y =3)= ………

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`(55)/(1024)`
`(55)/(4049)`
`(55)/(2048)`
NONE of these

Answer :A
22.

The point on y^(2)=x where tangent makes angle of measure (pi)/(4) with the positive X-axis is ………..

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`((1)/(4),(1)/(2))`
(2, 1)
(0, 0)
`(-1, 1)`

ANSWER :A
23.

Express 0.423 in the form of p/q, (whre p, q in I, q ne 0)

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ANSWER :`(419)/(990)`
24.

Find the maximum and minimum values, if any, of thefunctions given by f(x) = |x + 2| – 1

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ANSWER :`x=-2`, 0
25.

Let n!, the factorial of a positive integer n, be defined as the product of the integers 1, 2 ...., n. In words, n! = 1xx2xx...xxn What is the number of zeros at the end of the integer 10^(2)! +11^(2)!+12^(2)!+99^2!

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ANSWER :24
26.

Which of the following is//are correct order of bond angle:

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`NH_(3)gtNF_(3)`
`H_(2)OgtOCI_(2)gtOF_(2)`
`I_(3)^(ominus)gtI_(3)^(opluse)`
`Fhat(s)F"(AXIAL)gtFhatSF(EQUITORIAL) in" SF_(4)`

Answer :A::C::D
27.

If n letters are placed at random in n addressed envelops then the probability that all the letters are placed in correct envelops is

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ANSWER :`(1)/(N!)`
28.

Sum of the coefficients of terms of degree 13 in the expansion of(1+x)^(11) (1+y^(2)-z)^(10) is

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`.^(10)C_(3)`
`.^(10)C_(4)`
`.^(11)C_(3)`
`.^(11)C_(4)`

SOLUTION :REQUIRED sum of coefficient
`=` coefficient of `t^(15)` in `(1+t)^(11) (1+t^(2) - t)^(100)`
`=` coefficeint of `t^(13)` in `(1+t)(1+t^(3))^(10)`
`=` coefficient of `t^(13)` in `((1+t^(3))^(10) + t(1+t^(3))^(10))`
`=` coefficient of `t^(12)` in `(1+t^(3))^(10)`
`= .^(10)C_(4)`
29.

Let a function f:[0,5] to R be continuous, f(1)=3 and F be defined as : F(x)=int_(1)^(x)t^(2)g(t)dt, where g(t)=int_(1)^(t)f(u)"du". Then for the function F, the point x=1 is :

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a POINT of INFLECTION.
a point of LOCAL maxima.
a point of local MINIMA.
not a critical point.

Answer :C
30.

Foot of the perpendicular drawn from the origin to the plane passing through (1,0,0),(0,1,0)and(0,0,1) is

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`(3,3,3)`
`((1)/(2),(1)/(2),(1)/(2))`
`((1)/(3),(1)/(3),(1)/(3))`
`(2,2,2)`

ANSWER :C
31.

Which of the following function are continuous at x=0 ? [Note : sgn x denotes signum dunction od x.]

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`COS((pi)/(2)sgn|X|)+sgn|x|`
`cos((pi)/(2)sgn|x|)-sgn|x|`
`SIN((pi)/(2)sgn|x|)+sgn|x|`
`sin((pi)/(2)sgn|x|)-sgn|x|`

Solution :We have `cos((pi)/(2)sgn|x|)={{:(0","x!=0),(1","x=0):}`
`"As,"sgn|x|={{:(0","x!=0),(1","x=0):}rArrcos((pi)/(2)sgn|x|)+sgn|x|=1AAx INR`
`"Also,"cos((pi)/(2)sgn|x|)-sgn|x|={{:(-1","x!=0),(1","x=0):}`
`"As,"sin((pi)/(2)sgn|x|)-sgn|x|={{:(1","x!=0),(0","x=0):}rArrsin((pi)/(2)sgn|x|)+sgn|x|={{:(2","x!=0),(0","x=0):}`
`andsin((pi)/(2)sgn|x|)-sgn|x|=0AAx inR`.
32.

A radioactive substance 'A' converts to stable nuclei D by following series of reaction : AtoBtoCtoD Given : t_(1//2)"for"'A'=0.0693 days t_(1//2)"for"'B'=6930 days t_(1//2)"for"'C'=6.93 days Number of nuclei of 'D' present after 6930 days are, if initially 10^(20) nuclei of A is taken

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`10^(10)`
`(1)/(2)xx10^(20)`
`(1)/(2)xx10^(17)`
`10^(9)`

Solution :NUMBER of nuclei of 'D' formed=umber of nuclei of 'B' disintegrated `=(1)/(2)xx10^(20)""]`
33.

A radioactive substance 'A' converts to stable nuclei D by following series of reaction : AtoBtoCtoD Given : t_(1//2)"for"'A'=0.0693 days t_(1//2)"for"'B'=6930 days t_(1//2)"for"'C'=6.93 days Number of nuclei of 'C' formed in the 10 days are, if initially 10^(20) nuclei of A is taken

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`10^(18)`
`10^(16)`
`10^(17)`
`10^(19)`

SOLUTION :`Aoverset(lamda_(1))toBoverset(lamda_())toBoverset(lamda_(3))TOD`
`"SINCE "lamda_(1)gtgtlamda_(2) ltltlamda_(3)`
we can assume that all the 'A' has been converetd into 'B' in small duration
Number of moles of C formed = number of number of moles of 'B' dissociated
`DeltaB=lamda_(2)"N t"`
`=(ln2)/(6930)xx10^(20)xx10=10^(17)]`
34.

Statement-1: The period of sinx , cos x is 2pi and period of f(x)+g(x) is the LCM of the periods of f(x) and g(x)

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Statement-1 is TRUE, Statement-2 is True, statement-2 is a correct explanation for the statement-1 .
Statement-1 is True, Statement-2 is True, statement-2 is not a correct explanation for the statement-1 .
Statement-1 is True, Statement-2 is FALSE.
Statement-1 is False , Statement-2 is True.

Solution :Clearly, Statement-2 is true .
Now,
` sin""(pi)/(4)[x]=sin(2pi+(pi)/(4)[x])=sin""(pi)/(4)(8+[x])=sin""(pi)/(4)[x+8]`
`implies sin""(pi)/(4)[x]` is periodicwith period 3.
`cot""(pi)/(3)[x]=cot(pi+(pi)/(3)[x])=cot""(pi)/(3)[3+[x])=cot""(pi)/(3)[x+3]`
`implies cot""(pi)/(3)[x]` is PERIODIC with period 3.
and , ` cos""(pix)/(2)` is periodic with period `(2pi)/(pi//2)=4`
Using statement-2, period of F(x) is LCM of (8,3,4)=24
35.

int_(1)^(2)(1/x - 1/(2x^2))e^(2x) dx.

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ANSWER :`(E^(2)(e^(2)-2))/4`
36.

A coin is tossed three times. Find the probability of getting all heads.

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Answer :A COIN is tossed three times. `S={HHH,HT T, HTH,THH,T TH, THT,HHT,T T T}`
`|S|=8`
Let A be the EVENT of GETTING all heads
`thereforeA={HHH}impliesO.(A)=1`
`therefore P(A)=|A|/|S|=1/8`
37.

If P(A)=3/5andP(B)=1/5 find P(AcapB). If A and B are independent events

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ANSWER :`3/25`
38.

The position vector of the points A and B are respectively vec(a) and vec(b). Find the position vectors of the points which divide AB in trisection.

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ANSWER :`(VEC(B)+2vec(a))/(3);(vec(a)+2vec(b))/(3)`
39.

int_(0)^(2) (2x-2)/(2x-x) dx is equal to

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0
2
3
4

Answer :A
40.

A biased coin with probability p, 0 lt p lt 1 of heads is tossed until a head appears for the first time. If the probability that the number of tosses required is even is 2//5, then q equals

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`(1)/(3)`
`(2)/(3)`
`(2)/(5)`
`(3)/(5)`

ANSWER :A
41.

If ""^(n)C_(r-1):""^(n)C_(r):""^(n)C_(r+1)=2:4:5 then (n,r) is

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(10,4)
(9,7)
(8,3)
(7,2)

ANSWER :C
42.

If the normal of the plane makes angles (pi)/(4),(pi)/(4)" and "(pi)/(2) with positive X-axis, Y-axis and Z-axis respectively and the length of the perpendicular line segment form origin to the plane is sqrt(2), then the equation of the plane is ……......

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`x+y+z=sqrt(2)`
`x+y=2`
`x+y+z=1`
`x=sqrt(2)`

ANSWER :C
43.

If for a unit vector a.(x-a).(x+a)=12, then |x| is equal to

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4
2
`sqrt(13)`
`sqrt(11)`

Solution :Given |a|=1
[` :'`Itis a unitvector, mangnitude of unitvector is 1 ]
` therefore(x-a).(x+a)=12`
`IMPLIES x.x+x.a-a.x-a.a=12`
`[ :'a.a =|a|^(2) anda.b=b.a]`
`implies |x|^(2)-|a|^(2) = 12implies |x|^(2) -1^(2)=12`
`[ :'|a|=1 ` asit is unitvector ]
` | x|^(2)= 13gt |x|= sqrt(13)`
44.

Coefficient of x^5 in ( 1+ x)^21 + (1 + x)^22 + …….+ (1 + x)^30 is

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`""^51C_5`
`""^9C_5`
`""^31C_6 - ""^21C_6`
`""^30C_5 + ""^20C_5`

ANSWER :C
45.

Evaluate the following integrals (ii) int_(0)^(1)x^(2) sin^(-1) x dx

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ANSWER :`(PI)/(6) - (2)/(9)`
46.

Resolve the following into factor. a^(3) - 1/a^(3) + 4

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ANSWER :`(a - 1/a + 1) (a^(2) + 1/a^(2) - a + 1/a + 2)`
47.

Statement 1: Equation of the pair of lines bisecting the angle between the pair of lines ax ^(2)+by ^(2) + 2hxy+ 2gx+2fy+c =0 can be written as x ^(2)-y ^(2) - ((a-b))/(h) xy + lamda x + lamda x + mu y + c' =0.because Statement 2: Equatin of any pair of lines parallel to the lines ax ^(2)+by ^(2) +2hxy =0 is ax^(2) + 2hxy+ by^(2) +Ax+By+c^(n) =0,

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Stateme-1 is TRUE, Statement-2 is True, Statemetn-2 is correct explanation for Statement-1
Statement-1 is True, Statement-2 is True, Statement-2 is NOT a correct explanation for Statement-1
Statement-1 is True, Statement-2 is False
Statement-1 is False, Statement-2 is TURE

ANSWER :A
48.

Evaluate int_(0)^(2pi){cos(x)cos(2x)cos(2^(2)x)…cos(2^(n-1)x)cos(2^(n)-1)x}dx.

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ANSWER :`pi//2^(n-1)`
49.

Three distinct numbers a, b and c are chosen at random from the numbers 1, 2, …, 100. The probability that{:("List I","List II"),("a.a, b, c are in AP is","p. "(53)/(161700)),("b.a, b, c are in GP is","q. "(1)/(66)),("c. "(1)/(a). (1)/(b). (1)/(c) " are in GP is ","r. "(1)/(22)),("d.a + b + c is divisible by 2 is","s. "(1)/(2)):}

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`{:("a","B","c","d"),("q","s","s","R"):}`
`{:("a","b","c","d"),("r","q","q","p"):}`
`{:("a","b","c","d"),("q","p","p","s"):}`
`{:("a","b","c","d"),("q","s","p","r"):}`

Solution :`n(S) = .^(100)C_(3)`
a. 2b = a + c = even
This means that a and c are both even or both odd.
`n(E) = .^(50)C_(2) + .^(50)C_(2) = 50 XX 49`
b. Taking r = 2, 3, …, 10,
a, b, c can be in GP in 53 ways.
c.`(1)/(a), (1)/(b), (1)/(c)` are in GP = a, b, c are in GP
d. P(a + b + c is even) = `((.^(50)C_(3)+.^(50)C_(1) xx .^(50)C_(2))/(.^(100)C_(3))) = (1)/(2)`
50.

Consider oversetrarra=overset^^i+2overset^^j-3overset^^k,"" oversetrarrb=3overset^^i-overset^^j+2overset^^k "and " oversetrarrc=11 overset^^i+overset^^j:Find oversetrarra+oversetrarrb"and"oversetrarra.oversetrarrb

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SOLUTION :`veca+vecb=4overset^^i+overset^^j-overset^^k`
`veca.vecb=1xx3+2xx(-1)+(-3)xx2`