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| 17751. |
Area bounded by Curves |
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Answer» Correct Answer - 3 `A= underset(0)overset(4)(int) {(6x-x^(2))-(x^(2)-2x)} dx` `A= underset(0)overset(4)(int) (8x-2x^(2))dx` `A=[4x^(2) - 2/3 x^(3)]_(0)^(4)=64-128/3=64/3` sq. units |
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| 17752. |
Complex compound `[Cr(NCS)(NH_(3))_(5)][ZnCl_(4)]` will be -A. diamaganetic and shows linkage isomerismB. colourless and diamagneticC. green coloured and diamagneticD. green coloured and shows co-ordination isomerism. |
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Answer» Correct Answer - D `[overset(+3)(Cr)(NCS)(NH_(3))_(5)][underset(+2)(Zn)Cl_(4)]` `Cr^(+3) = [Ar] 4s^(0)3d^(3)` It has 3 unpaired `e^(-)` Green coloured and shows co-ordination isomerism |
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| 17753. |
Incorrect order of boiling point is -A. `HF gt HI gt HBr gt HCl`B. `H_(2)O gt H_(2)Te gt H_(2)Se gt H_(2)S`C. `Br_(2) gt Cl_(2) gt F_(2)`D. `CH_(4) gt GeH_(4) gt SiH_(4)` |
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Answer» Correct Answer - D `CH_(4) gt GeH_(4) gt SiH_(4)` |
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| 17754. |
`{:(MnO_(2)+KOH+O_(2)rarrunderset(("green"))(A)+H_(2)O),(A+Cl_(2)rarrunderset(("purple"))(B)+KCl):}` Select correct statement:-A. compound B is cloured due to change transfer and it is paramagnetic in nature.B. Compound B is `KMnO_(4)`. Tjere is no unparied `e^(-)` in MnC. Compound A is `K_(2)MnO_(4),K_(2)MnO_(4)` has tetrahedral shape.D. `KMnO_(4)` acts as oxidising agent. In acidic medium it form `Mn^(+2)` |
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Answer» Correct Answer - A `KMnO_(4)` is diamagnetic in nature. Compound B is coloured due to charge transfer and it is paramagnetic in nature. |
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| 17755. |
If `sum_(i=1)^(15)x_(i)=45,A=sum_(i=1)^(15)(x_(i)-2)^(2)` `B=sum_(i=1)^(15)(x_(i)-3)^(2)` and `C=sum_(i=1)^(15)(x_(i)-5)^(2)` then Statement 1: `min(A,B,C)=A` Statement 2: The sum of squares of deviations is least when taken from man.A. Statement 1: is True, Statement 2 is True , Statement 2 is a correct explanation for statement 1B. Statement 1 is True, Statement 2 is True Statement 2 is NOT a correct explanation for Statement 1C. Statement 1 is True, Statement 2 is FalseD. Statement 1 is False, Statement 2 is True |
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Answer» Correct Answer - D `sum_(i=1)^(n)(x_(i)-barx)^(2)` `implies "min" (A,B,C)=B` |
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| 17756. |
If `4sin^(-1)x+cos^(-1)x=pi`, then `x` is equal toA. `2/3`B. `1/3`C. `1/2`D. `2` |
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Answer» Correct Answer - C `3sin^(-1)x=pi-(pi)/2` `sin^(-1)x=(pi)/6,x=1/2` |
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| 17757. |
If `sum_(i=1)^(15)x_(i)=45,A=sum_(i=1)^(15)(x_(i)-2)^(2)`, `B=sum_(i=1)^(15)(x_(i)-3)^(2)` and `C=sum_(i=1)^(15)(x_(i)-5)^(2)` then Statement 1: `min(A,B,C)=A` Statement 2: The sum of squares of deviations is least when taken from man.A. Statement 1: is True, Statement 2 is True , Statement 2 is a correct explanation for statement 1B. Statement 1 is True, Statement 2 is True Statement 2 is NOT a correct explanation for Statement 1C. Statement 1 is True, Statement 2 is FalseD. Statement 1 is False, Statement 2 is True |
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Answer» Correct Answer - D `sum_(i=1)^(n)(x_(i)-barx)^(2)` `implies "min" (A,B,C)=B` |
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| 17758. |
If `x=9` is the chord of contact of the hyperbola `x^2-y^2=9` then the equation of the corresponding pair of tangents is (A) `9x^2-8y^2+18x-9=0` (B) `9x^2-8y^2-18x+9=0` (C) `9x^2-8y^2-18x-9=0` (D) ` `9x^2-8y^2+18x+9=0` |
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Answer» Correct Answer - 4 Let `x = 9` be the chord of contact of the given hyperbola with respect to the point `(x_(1), y_(1))`. Then its equation is given by `T=0` i.e. `x x_(1)-y y_(1)=9` `x x_(1)-y y_(1)=9` Comparing this equation to `x=9`, we get `x_(1)/1=y_(1)/0=1 implies x_(1)=1, y_(1)=0` Hence tangents are drawn from the point `(1, 0)`. So their combinaed equation is `S S_(1)=T^(2)` `(x^(2)-y^(2)-9) (-8)=(x-9)^(2)` `implies 9 x^(2)-8y^(2)-18x+9=0` |
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| 17759. |
If `f(x)=sin|x|-e^(|x|)` then at `x=0,f(x)` isA. Continuous but not differentiableB. Neither continuous nor differentiableC. Both continuous and differentiableD. Discontinuous but may be differentiable |
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Answer» Correct Answer - C `RHD=lim_(hrarr0)(sin|0+h|+e^(|0+h|)-(-1))/h` `=lim_(hrarr0) (sinh)/h-((e^(h)-1)/h)=1-1=0` Similarly LHD`=0` |
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| 17760. |
The no. of solutions of the equation `a^(f(x)) + g(x)=0` where a>0 , and g(x) has minimum value of 1/2 is :-A. OneB. TwoC. Infinitely manyD. Zero |
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Answer» Correct Answer - D `a^(f(x))=-g(x)le-1//2`, since `g(x)ge1//2` for all `x`. But this is not possible as `a^(f(x))gt0` for all `x`. Thus the number of solution is zero. |
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| 17761. |
Angle between diagonals of a parallelogram whose side are represented by `veca=2hati+hatj+hatk` and `vecb=hati-hatj-hatk`A. `cos^(-1)(1/3)`B. `cos^(-1)(1/2)`C. `cos^(-1) (4/9)`D. `cos^(-1)(5/9)` |
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Answer» Correct Answer - A Diagonals are `veca+vecb` and `veca-vecb` |
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| 17762. |
The distance between the origin and the normal to the curve `y=e^(2x)+x^(2)` at `x=0` isA. `2/(sqrt(3))`B. `2/(sqrt(5))`C. `2/(sqrt(7))`D. `1/(sqrt(5))` |
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Answer» Correct Answer - B `(dy)/(dx)=2e^(2x)+2ximplies((dy)/(dx))_(x=0)=2e^(@)+0=2` Slope of normal `=-1/2` at `x=0,y=1` Equation of normal `y-1=1/2(x-0)` `impliesx+2y-2=0` its distance from `(0,0)=2/(sqrt(5))` |
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| 17763. |
The function `f(x)=1+x(sinx)[cosx], 0ltxlepi//2`, where `[.]` denotes greatest integer functionA. is discontinuous is `(0,pi//2)`B. is strictly decreasing in `(0,pi//2)`C. is strictly increasing in `(0,pi//2)`D. has global maximum value 1 |
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Answer» Correct Answer - D For `0gtxlepi//2,[cosx]=0` Hence `f(x)=1` for all `xepsilon(0,pi//2)`. `f(x)` is continuous on `(0,pi//2)`. This function is neither strictly increasing nor strictly decreasing and its global maximum is 1. |
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| 17764. |
Consider the following statements Statement 1: The range of `log_(1)(1/(1+x^(2)))` is `(-oo,oo)` Statement 2: If `0ltxle1`, then range of `logx epsilon(-oo,0]` Which of the following is correctA. Statement 1: is True, Statement 2 is True , Statement 2 is a correct explanation for statement 1B. Statement 1 is True, Statement 2 is True Statement 2 is NOT a correct explanation for Statement 1C. Statement 1 is True, Statement 2 is FalseD. Statement 1 is False, Statement 2 is True |
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Answer» Correct Answer - D Range of `1/(1+x^(2))` is `(0,1]` is domain `R`. `:. log(1/(1+x^(2)))epsilon(-oo,0]` |
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| 17765. |
Consider the following statements Statement 1: The range of `log_(1)(1/(1+x^(2)))` is `(-oo,oo)` Statement 2: If `0ltxle1`, then `log_(1)=xepsilon(-oo,0]` Which of the following is correctA. Statement 1: is True, Statement 2 is True , Statement 2 is a correct explanation for statement 1B. Statement 1 is True, Statement 2 is True Statement 2 is NOT a correct explanation for Statement 1C. Statement 1 is True, Statement 2 is FalseD. Statement 1 is False, Statement 2 is True |
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Answer» Correct Answer - D Range of `1/(1+x^(2))` is `(0,1]` is domain `R`. `:. log(1/(1+x^(2)))epsilon(-oo,0]` |
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| 17766. |
If `y=tan^(-1)x+tan^(-1)(1/x)+cosec^(-1)x,xepsilon(-oo,-1)uu[1,oo)`, then `yepsilon`A. `[-pi,-(pi)/2)uu((pi)/2,pi]`B. `(-(pi)/2,(pi)/2)`C. `(0,pi)`D. `[0,(pi)/2)uu[(pi)/2,pi)` |
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Answer» Correct Answer - A `y=tan^(-1)x+(tan^(-1))1/x+cosec^(-1)x={((pi)/2+cosec^(-1)x,xgt0),(-(pi)/2+cosec^(-1)x,xlt0):}` if `xgt0`, then `(pi)/2ltylt-pi` if `xlt0`, then `-pileylarr(pi)/2` `:.yepsilon[-pi,-(pi)/2)uu((pi)/2,pi]` |
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| 17767. |
Find the greatest and least value of `(sin^-1x)^3+(cos^-1x)^3.`A. `(pi^(3))/32`B. `(pi^(3))/8`C. `(7pi^(3))/8`D. none of these |
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Answer» Correct Answer - C We have `(sin^(-1)x)^(3)+(cos^(-1)x)^(3)` `=(sin^(1)x+cos^(-1)x)^(3)-3sin^(-1)xcos^(-1)x(sin^(-1)x+cos^(-1)x)` `=(pi^(3))/8-=3(sin^(-1)xcos^(-1)x)(pi)/2` `=(pi^(3))/8-(3pi)/2x((pi)/2-sin^(-1)x)` `=(pi^(3))/8-(3pi^(2))/4sin^(-1)x+(3pi)/2(sin^(-1)x)^(2)` `=(pi^(3))/8+(3pi)/2[(sin^(-1)x)^(2)-(pi)/2sin^(-1)x]` `=(pi^(3))/8+(3pi)/2[(sin^(-1)x-(pi)/4)^(2)]-(3pi^(3))/32` `=(pi^(3))/32+(3pi)/2(sin^(-1)x-(pi)/4)^(2)` and since `(sin^(-1)x-(pi)/4)^(2)le(-(3pi)/4)^(2)` `:.` The greatest value is `(pi^(3))/32+(9pi^(2))/16xx(3pi)/2=(7pi^(3))/8` |
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| 17768. |
If `sin^(-1)(tan(pi)/4)-sin^(-1)(sqrt(3/y))-(pi)/6=0` and `x^(2)=y` then `x` is equal toA. `2`B. `4`C. `sqrt(2)`D. `sqrt(3)` |
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Answer» Correct Answer - A `sin^(-1)-sin^(-1)(sqrt(3/y))-(pi)/6=0` `impliessin^(-1)(sqrt(3/y))=(pi)/3implies(sqrt(3))/2=sqrt(3/y)` `impliesy=5impliesx=+-2` |
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| 17769. |
A circle touches the line `y = x` at the point `(2, 2)` and has it centre on y-axis, then square of its radius is |
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Answer» Correct Answer - 8 A circle touches ………… Equation of a circle touching the line `y = x at (2, 2)` is `(x-2)^(2)+(y-2)^(2)+lambda(x-y) = 0` `i.e. x^(2)y^(2)-(4-lambda)x- (4+lambda)y +8 =0` its centre `((4-lambda)/(2), (4+lambda)/(2))` lies on y-axis `:. (4-lambda)/(2) = 0` i.e. `lambda = 4` `:.` the circle is `x^(2)+y^(2)8y+8=0` `:.` radius `= sqrt(16-8) = sqrt(8)` |
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| 17770. |
Which of the following is not a unit of temperature?(a) Celsius(b) Fahrenheit(c) Therm(d) Rankine |
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Answer» Right choice is (c) Therm To explain I would say: Them is a unit of energy, 1 therm = 10^5 BTU. |
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| 17771. |
Which of the following is not a unit of pressure?(a) Bar(b) N/m^2(c) Kg/m^2(d) Torr |
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Answer» Right choice is (c) Kg/m^2 For explanation: Pressure is force per unit area so Kg/m^2 cannot be a unit of pressure. |
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| 17772. |
Which of the following is greatest?(a) 10^oC(b) 10^oR(c) 10^oF(d) 10 K |
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Answer» Right answer is (a) 10^oC For explanation: 10^oC = 283 K = 50^oF = 510^oR, => 10^oC is greatest. |
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| 17773. |
If change in temperate is 180 degree Rankine, what is the change in temperature in degree Celsius?(a) 100^oC(b) 180^oC(c) 212^oC(d) 273^oC |
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Answer» The correct choice is (a) 100^oC The explanation is: ∆TR = 1.8∆TC, => Change in temperature = 180/1.8 = 100^oC. |
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| 17774. |
Out of `25` consecutive natural numbers, two numbers can be chosen in `lambda` ways such that their "sum" is divisible by `2`. Then `lambda//36` is. |
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Answer» Correct Answer - 4 Out of `25` consecutive ……….. `lambda = ^(12)C_(2)+ ^(13)C_(2) = 144` |
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| 17775. |
If change in temperate is 212 degree Fahrenheit, what is the change in temperature in degree Rankine?(a) 100^oR(b) 212^oR(c) 273^oR(d) 460^oR |
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Answer» The correct answer is (b) 212^oR To explain I would say: Since ∆TR = ∆TF, => 212^oF = 212^oR. |
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| 17776. |
If `x, 2x+ 2, 3x + 3 `are in `G.P. ,` then the fourth term is (A) `27` (B) `-27` (C)`13.5` (D)`-13.5`A. `27`B. `-27`C. `13.5`D. `-13.5` |
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Answer» Correct Answer - D If `x, 2x+2,3x+3` are …………. Given that `x, 2x+2, 3x+3` are in G.P. Therefore, `(2x+2)^(2)= x(3x+3)` `implies x^(2)+5x+4 = 0` `implies (x+4)(x+1) = 0` `implies x = -1 -4` Now first term `a = x`, second trem `ar = 2(x+1)` `implies r= (2(x+1))/(x)`, then `4^(th)` term `= ar^(3)` `= x[(2(x+1))/(x)]^(-3) = (8)/(x^(2))(x+1)^(3)` Putting `x = -4`, We get `T_(4)= (8)/(16)(-3)^(3) = -(27)/(2)= - 13.5` |
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| 17777. |
What is the 40^oF in degree Rankine?(a) 313^oR(b) 460^oR(c) 500^oR(d) 672^oR |
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Answer» The correct answer is (c) 500^oR To explain I would say: Temperature = 40 + 460 = 500^oR. |
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| 17778. |
What is the temperature 100^oC in degree Rankine?(a) 100^oR(b) 212^oR(c) 560^oC(d) 672^oC |
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Answer» Correct answer is (d) 672^oC The explanation is: Temperature = 9(100)/5 + 32 + 460 = 672^oR. |
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| 17779. |
If `x` is real and satisfies `x +2lt sqrt(x +4)`, thenA. `x lt - 2`B. `x gt 0`C. `-3lt x lt 0`D. `-3 lt x lt 4` |
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Answer» Correct Answer - B If `x` is real and satisfies ……….. Given `x+2 gt sqrt(X +4) implies (x +2)^(2)gt (x+4)` `implies x^(2)+4x+4gt x +4 implies x^(2)+3x gt 0` `implies x(x+3)gt 0 implies x lt - 3 or x gt 0` `implies x gt 0 (x+2` must be positive). |
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| 17780. |
If `alpha` and `beta` are solutions of `sin^2 x + a sin x+b=0` as well as that of `cos^2x + c cosx + d =0` then `sin(alpha + beta) ` is equal toA. `(2bd)/(b^(2)+d^(2))`B. `(a^(2)+c^(2))/(2ac)`C. `(b^(2)+d^(2))/(2bd)`D. `(2ac)/(a^(2)+c^(2))` |
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Answer» Correct Answer - D If `alpha` and `beta` are ………….. According to the given condition, `sin alpha + sin beta = -a` and `cos alpha+cos beta= -c` . `implies 2 sin. (alpha+beta)/(2)cos.(alpha-beta)/(2)= -a &` `2cos.(alpha+beta)/(2)cos.(alpha-beta)/(2)= -c` `implies tan. (alpha+beta)/(2)= (a)/(c ) implies sin. (alpha + beta)` `(2tan.(alpha+beta)/(2))/(1+tan.^(2)(alpha+beta)/(2)) = (2ac)/(a^(2)+c^(2))` |
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| 17781. |
Let `alpha` and `beta` are roots of `x^(2) - 17x - 6 = 0` with `alpha gt beta, if a_(n) = alpha^(n+2)+beta^(n+2)` for `n ge 5` then the value of `(a_(10)-6a_(8)-a_(9))/(a_(9))`A. `6`B. `16`C. `12`D. `8` |
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Answer» Correct Answer - B Let `alpha` and `beta` ……….. Let `alpha` and `beta` asre roots of `x^(2)-17x-6=0` `alpha^(2)-17alpha-6=0` `alpha^(n+2)-17alpha^(n+1)-6alpha^(n)=0` `beta^(n+2)-17beta^(n+1)-6beta^(n)=0` By (1) and (2) `a_(n)-17a_(n-1)-6a_(n-2)=0` `a_(10)-17a_(9)-6a_(8) = 0` `a_(10)-6a_(8)-a_(9)=16a_(9)` `implies (a_(10)-6a_(8)-a_(9))/(a_(9)) = 16` |
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| 17782. |
If `x in(1, 30)` and `(1+tan x^(@))(1+tan(x+1)^(@))...(1+tan(x+44)^(@)) = 2^(23)` then value of x isA. `0`B. `1`C. `2`D. `3` |
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Answer» Correct Answer - B If `x epsilon (1, 30)` and ………… `x = 1` `(1+tan x^(@))(1+tan(x+1)^(@))…. (1+tan(x+44)^(@))ge(1+tan 1^(@))` `(1+tan 2^(@)) ……….. (1+tan 45^(@))` Now `(1+tan1^(@))(1+tan 44^(@))(1+tan2^(@))(tan 43^(@)+1)`……….. using `(1+tan x^(@))(1+tan(45-x^(@)))=2` `(1+tan 1^(@))(1+tan 2^(@))............ (1+tan 45^(@)) = 2^(23)` |
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| 17783. |
Let S=`4/19+44/(19)^2+444/(19)^3+...oo` then find the value of SA. `(38)/(81)`B. `(4)/(19)`C. `(2)/(9)`D. `(36)/(81)` |
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Answer» Correct Answer - A Let `S =` ………… `S = (4)/(19)+(44)/(19^(2))+(444)/(19^(3))+………..oo` `(S)/(19)=(4)/(19^(2))+(44)/(19^(3))+………oo` Subtracting, we get `S. (18)/(19) = (4)/(19)+(40)/(19^(2))+(400)/(1^(3))+` …………. `=(4)/(19)[1+(10)/(9)+((10)/(9))^(2)+..........]` `= (4)/(19)[(1)/(1-(10)/(19))] = (4)/(9) implies S = (76)/(162) = (38)/(81)` |
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| 17784. |
For the solution of `[x+2]+[x-8]>0`is (`[dot]`is greatest integer function)`[3,oo)`2. `[4,oo)`3. [1,3] 4 . (3,4) 5. RA. `[3, oo)`B. `[4, oo)`C. `[1, 3]`D. `(3,4)` |
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Answer» Correct Answer - B For x, the solution of ………….. `[x+2]+[x-8]gt 0 implies [x]+2+[x]-8gt0` `implies [x]gt3 implies x epsilon [4, oo)` |
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| 17785. |
Let S=`4/19+44/(19)^2+444/(19)^3+...oo` then find the value of SA. `(38)/(81)`B. `(4)/(19)`C. `(36)/(871)`D. `(4)/(9)` |
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Answer» Correct Answer - A The sum of the series ……….. `S = (4)/(19)+(44)/(19^(2))+………… oo` `(S)/(19) = (4)/(19^(2))+(44)/(19^(3))+………….oo` `(18S)/(19)= (4)/(19)[1+(10)/(19)+(10^(2))/(19^(2))+………..oo]` `s = (38)/(81)` |
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| 17786. |
The homologue of Ethyl propanoate is :A. Propyl ethanoateB. Methyl butanoateC. Ethyl butanoateD. Isopropyl ethanoate |
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Answer» Correct Answer - C `underset(("Ethyl propanoate"))(CH_3-CH_2-oversetoverset(O)(||)C-O-CH_2-CH_3) " " & " " underset(("Ethyl butanoate"))(CH_3-CH_2-CH_2-oversetoverset(O)(||)C-O-CH_2-CH_3) `are homologue |
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| 17787. |
Choose the strongest base among the following :A. B. C. D. |
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Answer» Correct Answer - D Only in (D) the l.p of N atoms is not involved in resonance with benzene ring. |
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| 17788. |
Acidic strength of marked hydrogen of following compound in decreasing order is A. IgtIIgtIIIgtIVB. IIgtIgtIIIgtIVC. IIIgtIIgtIgtIVD. IIgtIIIgtIVgtI |
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Answer» Correct Answer - B Acidic strength `prop` Stability of conjugate base. |
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| 17789. |
has correct IUPAC name as :A. 3-Carbamoylbenzene-1-carbonitrileB. 3-Cyanobenzene-1-carboxamideC. 3-CyanobenzamideD. 3-Aminocarbonylcyanobenzene |
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Answer» Correct Answer - B (1)`-oversetoverset(O)(||)C-NH_2`, when attached to a ring, it is named as carboxamide. (2)`-oversetoverser(O)(||)C-NH_2` has higher priority than -C=N (3)-C=N has prefix cyano |
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| 17790. |
Match the order given in column (I) with the property(les) in column (II). `{:("Column I","Column II"),((A)Rb_2CO_3gtK_2CO_3gtNa_2CO_3,(p)"Solubility of salts in water"),((B)SrSO_4gtCaSO_4gtMgSO_4,(q)"Thermal stability of salts"),((C )RbgtKgtNa,(r)"Softness of metals"),((D)BegtMggtCa,(s)"Hydration energy of metals"),(,(t)"Ionisation energy of metals "):}` |
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Answer» Correct Answer - A-p,q ; B-q ; C-r ; D-s,t (A)Down the group the decrease in the lattice energy is more as compared to that of hydration energy with increase in size of cations.So the solubility order is correct.Similarly the thermal stability of the oxo-salts increases with increase in metallic character.So the thermal stability order is correct. (B)The correct order of solubility is `MgSO_4 gt CaSO_4 gt SrSO_4` as in this case decrease in hydration energy is more as compared to that of lattice energy. The orde of thermal stability is correct, as down the group metallic character increases and thus the thermal stability of oxo-salts increases. (C )Down the group strength of metallic bond decreases Due to this there occurs a decrease in close packing of atoms in crystal lattice from Li to Cs and thus softness increase donw the group. (D)hydration energy `prop 1/ ("size of atom")`So BegtMggtCa is correct order. Ionisation energy `prop 1/("Size of atom")` So BegtMggtCa is correct order. |
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| 17791. |
Based on given information `DeltaG^(@)_(f)(CaO) =- 604.2kJ//mol` and `DeltaG^(@)_(f)(A1_(2)O_(3)) =- 1582kJ//mol`, which of the following is feasible?A. `2Ca +A1_(2)O_(3)rarr2A1+3CaO`B. `3CaO +2A1 rarrA1_(2)O_(3) +3Ca`C. Both `(a)` and `(b)`D. None of the above |
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Answer» Correct Answer - A `3Ca +A1_(2)O_(3)rarr 2A1 +3CaO` `DeltaG^(@) = 3xxDeltaG^(@) (CaO) - DeltaG^(@) (A1_(2)O_(3))` `= 3xx(-604.2)-(-1582)` `=- 1812 + 1582` `=- 230kJ` `DeltaG^(@)` is negative. Hence, this reaction is feasible. |
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| 17792. |
An isolated system (a) is a specified region where transfer of energy and/or mass take place (b) is a region of constant mass and only energy is allowed to cross the boundaries (c) cannot transfer either energy or mass to or from the surroundings (d) is one in which mass within the system is not necessarily constant (e) none of the above. |
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Answer» (c) cannot transfer either energy or mass to or from the surroundings |
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| 17793. |
An open system is one in which (a) heat and work cross the boundary of the system, but the mass of the working substance does not (b) mass of working substance crosses the boundary of the system but the heat and work do not (c) both the heat and work as well as mass of the working substances cross the boundary of the system (d) neither the heat and work nor the mass of the working substances cross the boundary of the system. |
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Answer» (c) both the heat and work as well as mass of the working substances cross the boundary of the system |
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| 17794. |
When two bodies are in thermal equilibrium with a third body they are also in thermal equilibrium with each other. This statement is called (a) Zeroth law of thermodyamics (b) First law of thermodynamics (c) Second law of thermodynamics (d) Kelvin Planck’s law. |
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Answer» (a) Zeroth law of thermodyamics |
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| 17795. |
In an extensive property of a thermodynamic system (a) extensive heat is transferred (b) extensive work is done (c) extensive energy is utilised (d) all of the above (e) none of the above. |
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Answer» (e) none of the above. |
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| 17796. |
Which of the following is an intensive property of a thermodynamic system ? (a) Volume (b) Temperature (c) Mass (d) Energy. |
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Answer» (b) Temperature |
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| 17797. |
A definite area or space where some thermodynamic process takes place is known as (a) thermodynamic system(b) thermodynamic cycle (c) thermodynamic process (d) thermodynamic law. |
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Answer» (a) thermodynamic system |
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| 17798. |
Which of the following is correct ?A. For a reversible reaction for which `Delta_(f)H = -ve` B. For reversible reaction for which `Delta_(f)H = +ve` C. D. Activation energy of a reaction is a barrier to energy tranfer (KE to PE) between reacting molecules that must be overcome, which is due to need of bonds stretch as well as steric repulsions. |
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Answer» Correct Answer - D Graph in A is plotted for endothermic reaction and graph in B is plotted for exothermic reactions actually. (C ) `E_(a_(1)) lt E_(a_(2)) lt E_(a_(3))` is correct. |
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| 17799. |
Assertion : Density of `Mg` is more than that of `Ca`. Reason : It is due to the presence of `3d-` orbital.A. If both assertion and reason are true and the reason is the correct explanation of the assertion.B. If both assertion and reason are true but reason is not the correct explanation of the assertion.C. If assertion is true but reason is false.D. If assertion is false but reason is true. |
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Answer» Correct Answer - C The density of alkaline earth metals decreases from `Be` to `Ca`. Alkaline earth metals have `ns^2` configuration. |
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| 17800. |
One mixing `500 mL` of `10^-6 M Ca^(2+)` ion and `500 mL` of `10^-6 MF^-` ion, no precipitate of `CaF_2` will be obtained. `K_(sp) (CaF_2 = 10^-18)`. If `K_(sp)` is greater than ionic product, a percipitate will develop.A. If both assertion and reason are true and the reason is the correct explanation of the assertion.B. If both assertion and reason are true but reason is not the correct explanation of the assertion.C. If assertion is true but reason is false.D. If assertion is false but reason is true. |
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Answer» Correct Answer - C `[Ca^(2+)][F^-]^2 = [(500 xx 10^-6)/(100)] xx [(500 xx 10^-6)/(1000)]^2` =`(1)/(8) xx 10^-18 = 0.12 xx 10^-18 lt K_(sp)` Thus, precipitation will not take place. |
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