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Recent questions tagged sec-e
Questions
On Q the set of all rational numbers, a binary operation $\ast$ is defined by $a \ast b=\frac{ab}{5}$ for all $a, b \in Q $. Find the identity element $\ast$ in Q. Also prove that every non-zero element of Q is invertible.
cbse
class12
maths
sec-e
ch1
asked
Nov 20, 2016
by
priyanka.c
1
answer
Find the shortest distance between the line $l_ 1$ and $l_2$ given by: $\overrightarrow {r} = \hat{i} +2\hat{j} -4\hat{k} + \lambda (2 \hat{i} + 3 \hat {j} + 6 \hat {k}) and \overrightarrow {r }= 3\hat{i} + 3\hat{j} -5\hat{k} + \mu(2\hat{i} + 3\hat{j} + 6\hat{k}) $
cbse
class12
maths
sec-e
ch10
asked
Nov 20, 2016
by
priyanka.c
1
answer
Evaluate : $\begin{align*}\int_4^9 \frac{\sqrt x}{(30 - x^{\frac{3}{2}})^2} dx \end{align*}$
cbse
class12
maths
sec-e
ch7
asked
Nov 20, 2016
by
priyanka.c
1
answer
Find the value of k if f(x) is continuous at $x = \frac{\pi}{2}$, when $f(x) =\begin{cases}\frac{k \cos x}{\pi - 2x }\;;\; x \neq \frac{\pi}{2} \\ 3 ,\; \; \; \; \; \; \; \; \; x = \frac{\pi}{2} \end{cases}$
cbse
class12
maths
sec-e
ch5
asked
Nov 20, 2016
by
priyanka.c
1
answer
If $ A = \begin{bmatrix} \cos\theta & -\sin\theta \\ \sin\theta & \cos\theta \end{bmatrix}$, then find the value of $\theta$ satisfying the equation $A^T + A = I_2$
cbse
class12
maths
sec-e
ch3
asked
Nov 20, 2016
by
priyanka.c
1
answer
Two eggs are drawn successively with replacement from a lot containing 10% defective eggs. Find the probability that there is at least one defective egg.
cbse
class12
maths
sec-e
ch13
asked
Nov 19, 2016
by
priyanka.c
1
answer
Find the vector and Cartesian equation of the line through the point (5, 2, -4) and which is parallel to the vector $3 \hat{i} +2 \hat{j} -8 \hat{k}$
cbse
class12
maths
sec-e
ch10
asked
Nov 19, 2016
by
priyanka.c
1
answer
$\begin{align*}\int_0^1 \frac{\tan^{-1} x}{1+x^2} dx \end{align*}$
cbse
class12
maths
sec-e
ch7
asked
Nov 19, 2016
by
priyanka.c
1
answer
Fine the maximum and minimum value of $f(x) = x + \sin 2x $ in the invervat $0, 2\pi $
cbse
class12
maths
sec-e
ch6
asked
Nov 19, 2016
by
priyanka.c
1
answer
Differentiate $\tan^-1 \frac{[\sqrt{1+x^2} + 1}{x}], x \neq 0$
cbse
class12
maths
sec-e
ch2
asked
Nov 18, 2016
by
priyanka.c
1
answer
Find the equation of the line joining (1,3) and B (0, 0) using determinants and find K if D (K,0) is a point such that area of $\triangle ABD$ is 3 sq. units
cbse
class12
maths
sec-e
ch4
asked
Nov 18, 2016
by
priyanka.c
1
answer
Show that function $f : R \to R$ given by $f(x) = x^3 + x $ I a bijection.
cbse
class12
maths
sec-e
ch1
asked
Nov 18, 2016
by
priyanka.c
1
answer
$\begin{align*}\int \frac{dx}{\sqrt {x^2 - a^2}} \end{align*}$
cbse
class12
maths
sec-e
ch7
asked
Nov 18, 2016
by
priyanka.c
1
answer
Two cards are drawn without replacement from a well shuffled pack of 52 cards. Find the probability that one is spade and other is a queen of red colour.
cbse
class12
maths
sec-e
ch13
asked
Nov 18, 2016
by
priyanka.c
1
answer
A line passes through (2, -1, 3) and is perpendicular to the line $\overrightarrow {r} = ( {\hat{i} + \hat {j} - \hat{k}}) + \lambda (2\hat{i} - 2\hat{j} +\hat{k}) $ and $\overrightarrow {r} = (2\hat{i} - \hat{j} -3\hat {k}) +\mu (\hat{i} + 2 \hat{j} +2\hat{k})$. Obtain its equation.
cbse
class12
maths
sec-e
ch10
asked
Nov 18, 2016
by
priyanka.c
1
answer
If $\overrightarrow {a} = \hat{i} + 2\hat{j} + 3\hat{k}$ and $\overrightarrow {b} = 2\hat{i} + 4\hat{j} - 5\hat{k}$ represents two adjacent sides of a parallelogram, find unit vectors parallel to the diagonals of the parallelogram.
cbse
class12
maths
sec-e
ch10
asked
Nov 18, 2016
by
priyanka.c
1
answer
If $A=\begin{bmatrix} 9 & 1 \\ 7 & 8 \end{bmatrix} $, $B =\begin{bmatrix} 1 & 5 \\ 7 & 12 \end{bmatrix}$ find matrix C such that 5A + 3B + 2C is a null matrix.
cbse
class12
maths
sec-e
ch3
asked
Nov 17, 2016
by
priyanka.c
1
answer
If $\cos^{-1} x + cos^{-1} y + cos^{-1} z = \pi $ , Evaluate $x^2 + y^2 + z^2 + 2xyz$
cbse
class12
maths
sec-e
ch2
asked
Nov 17, 2016
by
priyanka.c
1
answer
If the function $ f: [1, \alpha) \ implies [ 1, \alpha)$ defined by $f(x) = 2^{x(x-1)}$ is invertible, find $f^{-1}(x)$
cbse
class12
maths
sec-e
ch1
asked
Nov 17, 2016
by
priyanka.c
1
answer
$\begin{equation} \int\limits_0^1 \sin^{-1} x \; \mathrm{d} x \end{equation}$
cbse
class12
maths
sec-e
ch7
asked
Nov 17, 2016
by
priyanka.c
1
answer
If the points $A(-1, 3, 2),\; B(-4, 2, -2)$ and $C (5, 5, \lambda)$ are collinear, find the value of $\lambda$
cbse
class12
maths
ch11
sec-e
asked
Nov 16, 2016
by
priyanka.c
1
answer
Differentiate $a^x$ w.r.t x, where a is a constant
cbse
class12
maths
ch5
sec-e
asked
Nov 16, 2016
by
priyanka.c
1
answer
$\tan ^{-1}x +\tan^{-1} \frac{2x}{1-x^2} = 3 \tan ^{-1}(x) \;, |x| < \frac{1}{\sqrt 3}$ . Is this true ? Justify.
cbse
class12
maths
ch2
sec-e
asked
Nov 16, 2016
by
priyanka.c
1
answer
Let f : N $\to$ Y be a function defined as $f(x) = 4x + 3f(x)=4x+3$ where $Y = \{ y \in N ; y = 4x + 3Y=\{ y \in N; y= 4x+3$ for some $ x \in N \}x \in N \}$. If 'f' is invertible.
cbse
class12
maths
ch1
sec-e
asked
Nov 14, 2016
by
priyanka.c
1
answer
$\begin{align*}\int \frac{\sin 4x}{ \sin x} dx \end{align*}$
cbsc
class12
maths
ch7
sec-e
asked
Nov 13, 2016
by
priyanka.c
1
answer
Form the differential equation representing family of curves $y = A \cos (x + B)$ where A and B are parameters
cbsc
class12
maths
ch9
sec-e
asked
Nov 13, 2016
by
priyanka.c
1
answer
Prove that the points A, B and C with position vectors $\overrightarrow{a}, \overrightarrow{b} and \overrightarrow{c}$ respectively are collinear if and only if $\overrightarrow{a} \times \overrightarrow{b} + \overrightarrow{b} \times \overrightarrow{c} + \overrightarrow{c} \times \overrightarrow{a} = 0$
cbsc
class12
maths
sec-e
ch10
asked
Nov 13, 2016
by
priyanka.c
2
answers
It is given that a function $f{x} = x^3 - 6x^2 + ax+ b $ on [1,3] , Rolle's theorem holds with $c = 2 + \frac{1}{\sqrt3}$. Find the value of a and b if f(1) = f(3) = 0
cbsc
class12
maths
sec-e
ch5
asked
Nov 10, 2016
by
priyanka.c
1
answer
Differentiate w . r . t x $\tan^{-1}\bigg[\large\frac{1-\cos x}{sin x}\bigg]; -\pi < x < \pi$
cbsc
class12
maths
sec-e
ch-5
asked
Nov 10, 2016
by
priyanka.c
1
answer
Solve for $x . \begin{vmatrix} x+a & x & x \\ x & x+a & x \\ x & x & x+a \end{vmatrix} = 0 $
cbsc
class12
maths
ch-4
sec-e
asked
Nov 10, 2016
by
priyanka.c
1
answer
Let $F(x) =\begin{pmatrix} \cos x & -\sin x & 0 \\ \sin x & cos x & 0 \\ 0 & 0 & 1 \end{pmatrix} $ Show that F(x) F(y) = F (x+y)
cbsc
class12
maths
ch-3
sec-e
asked
Nov 10, 2016
by
priyanka.c
1
answer
Account for the following: i)Fluorine does no show variable oxidation states while other members of the halogen family exhibit variable oxidation states. ii)Iodine is more soluble in $KI$ solution than in water. iii)Why do boiling points of noble gases increases down the group? iv)Why ammonia is a good complexing agent? v)Nitric oxide(NO) is a colourless gas becomes brown when released in air.
cbse
class12
chemistry
sec-e
ch-8
d-and-f-block-elements
asked
Nov 10, 2016
by
meena.p
1
answer
a)i)The resistance of a conductivity cell containing $0.001\;M\; KCl$ solution at $298\;K$ is $1500 \Omega$. What is the cell constant, if the conductivity of $0.001\;M\; KCl$ solution at $298\;K$ is $0.146 \times 10^{-3}\;S\;cm^{-1}$? ii)Explain with one example each the terms weak and strong electolytes iii)The standard reduction potential values of three metallic cations $X,Y, Z$ are $+0.52, − 3.03, − 1.18 V$ respectively. What will be the order of reducing power of the corresponding metals? b) Distinguish between rate expression and rate constant of a reaction
cbse
class12
chemistry
sec-e
ch-11
chemical-kinetics
asked
Nov 10, 2016
by
meena.p
1
answer
Prove that $ \cos^{-1}x = 2 \sin^{-1} \sqrt{\frac{1-x}{2}}$
cbsc
class12
maths
ch-2
sec-e
asked
Nov 10, 2016
by
priyanka.c
1
answer
(a) Bring out the following conversions:. (i) 4-nitrotoluene to 2-bromobenzoic acid. (ii) Ethylcyanide to 1- phenyl propanone. (b) Give a reason for the following : (i) Chloroacetic acid is more acidic than acetic acid. (ii) Carboxylic acids have higher boiling point than alcohols. (iii) 4-nitrobenzoic acid is more acidic than 4-methoxy benzoic acid.
cbse
class12
chemistry
sec-e
ch-12
aldehydes-ketones-and-carboxylic-acids
asked
Nov 10, 2016
by
meena.p
1
answer
(a) Compare non transition and transition elements on the basis of their (i) Variability of oxidation states (ii) stability of oxidation states. (b) Give chemical reactions for the following observations: (i) Potassium permanganate is a good oxidising agent in basic medium. (ii) Inter convertibility of chromate ion and dichromate ion in aqueous solution depends Upon pH of the solution. (iii) Potassium permanganate is thermally unstable at $513\;K$.
cbse
class12
chemistry
sec-e
ch-8
d-and-f-block-elements
asked
Nov 10, 2016
by
meena.p
1
answer
(I)(a) Calculate the boiling point of a solution containing $0.61\;g$ of benzoic acid in $5\; g$ of $CS_2$ .Assuming $84\%$ dimerisation of acid. The boiling point and $K_b$ of $CS_2$ are $46.2^{\circ}0C$ and $2.3\; K\; Kg \;mol^{-1}$ respectively. (b) State Raoult's law for the solution containing non-volatile solute. Give its mathematical expression also. (II) A solution of $KMnO_4$ on reducing yields either a colourless solution or a brown precipitate or a green solution depending on $PH$ of the solution . What different stages of the reduction do these represent and how are they carried out ?
cbse
class12
chemistry
sec-e
ch-4
chemical-kinetics
asked
Nov 10, 2016
by
meena.p
1
answer
(a) Write a suitable chemical equation to complete each of the following transformations: (i) Butan-1-ol to butanoic acid . ( ii) 4 -Methylacetophenone to benzene -1,4-dicarboxylic acid (b) Suggest a reagent for conservation of ethanol to ethanoic acid
cbse
class12
chemistry
sec-e
ch-11
alcohols-phenols-and-ethers
asked
Nov 9, 2016
by
meena.p
1
answer
(a)Define the following terms : (i) Mole fraction (ii) Ideal solution (b) For the reaction $A \to B$ ,the rate of reaction becomes twenty seven times when the concentration of A is increased three times . What is the order of the reaction ?
cbse
class12
chemistry
sec-e
ch-4
chemical-kinetics
asked
Nov 9, 2016
by
meena.p
1
answer
(a)Draw the molecular structure of the following compounds : $(i)N_2O_5 (ii) X_eOF_4$ (b) Why do the d-block elements exhibits a large number of oxidation states than f - block elements
cbse
class12
chemistry
sec-e
ch-8
d-and-f-block-elements
asked
Nov 8, 2016
by
meena.p
1
answer
(a) Illustrate the following reactions giving a suitable example for each : (i) Cross aldol condensation (ii) Decarboxylation (b) Give Simple tests to distinguish between the following pairs of compounds : (i) Pentan -2-one and pentan -3-one (ii) Benzaldehyde and Acetophenone (iii) Phenol and Benzoic acid .
cbse
class12
chemistry
sec-e
ch-11
alcohols-phenols-and-ethers
asked
Nov 2, 2016
by
meena.p
1
answer
(a) Define molar conductivity of a solution and explain how molar conductivity changes with change in concentration of solution for a weak and a strong electrolyte (b) The resistance of a conductivity cell conatining $0.001\;M\;KCL$ Solution at $298\;K$ is $1500 \;\Omega$ . What is the cell constant if the conductivity of $0.001\;M\;KCl$ solution at $298\;K$ is $0.146 \times 10^{-3} \;S \;cm^{-1}$ ?
cbse
class12
chemistry
sec-e
ch-3
electrochemistry
asked
Nov 1, 2016
by
meena.p
1
answer
Write chemical equation for the following conversions : (i) Nitro benzene to benzoic acid. (ii) Benzyl chloride to 2-phenylethanamine. (iii) Aniline to benzyl alcohol .
cbse
class12
chemistry
sec-e
ch-12
aldehydes-ketones-and-carboxylic-acids
asked
Oct 26, 2016
by
meena.p
1
answer
What type of a battery is the lead storage battery ? write the anode and the cathode reaction occurring in a lead storage battery when current is drawn from it .
cbse
class12
chemistry
sec-e
ch-3
electrochemistry
asked
Oct 26, 2016
by
meena.p
1
answer
(a)The rate constant for a reaction of zero order in A is $0.0030\;mol L^{-1}S^{-1}$ How long will it take for the initial concentration of A to fall from $0.10\;M$ to $0.075\;M$ ? (b)What type of colloidal sols are formed in the following : (i) Sulphur vapours are passed through colled water (ii) White of an egg is mixed with water . (iii) Soap solution
cbse
class12
chemistry
sec-e
ch-4
chemical-kinetics
asked
Oct 25, 2016
by
meena.p
1
answer
(a) Give names of the reagents to bring about the following transformations : (i) Ethanoic acid to ethanol (ii) Propan -1-ol to propanal (iii) Pent -3-en-2-ol pent-3-en-2-one (iv) Sodium benzoate to benzene (b) Arrange in the following in increasing order of : (i) Methanal , Propanal, Butanone, ethanal,Propanone(Nucleophilic addition reaction ) (ii) Formaldehyde , Acetone , Acetaldehyde (reactivity towards HCN) (iii) Acetophenone, p- tolualdehyde, p-nitrobenzaldehyde, Benzaldehyde(nucleophilic addition reaction ).
cbse
class12
chemistry
sec-e
ch-11
alcohols-phenols-and-ethers
asked
Oct 24, 2016
by
meena.p
1
answer
Give chemical reactions for the following observations: (i) Potassium permanganate is a good oxidising agent in basic medium. (ii) Inter-convertibility of chromate ion and dichromate ion in aqueous solution depends upon pH of the solution . (iii) Potassium permanganate is thermally unstable at 513 K
cbse
class12
chemistry
sec-e
ch-8
d-and-f-block-elements
asked
Oct 24, 2016
by
meena.p
1
answer
(i)What is the freezing point of $0.4 $ molal solution of acetic acid in benzene in which it dimerises to the extent of $85\%$ Freezing point of benzene is $278.4 \;k$ and its molar heat of fusion is $10.042\;kj\; mol^{-1}$ (ii) Write balanced chemical equation for the following reactions : (a) Thermal decomposition of ammonium dichromate. (b) Reaction of $Cl_2$ with cold and deleted NaOH (c) When phosphine is passed through mercuric chloride solution .
cbse
class12
chemistry
sec-e
ch-4
chemical-kinetics
asked
Oct 24, 2016
by
meena.p
1
answer
(A)(a) Compare non transition and transition elements on the basis of their (i) Variability of oxidation states (ii) stability of oxidation states. (b) Give chemical reactions for the following observations: (i) Potassium permanganate is a good oxidising agent in basic medium. (ii) Inter convertibility of chromate ion and dichromate ion in aqueous solution depends Upon pH of the solution. (iii) Potassium permanganate is thermally unstable at $513\;K$. (B) Why do the d - block elements exhibit a large number of oxidation states than f- block elements
cbse
class12
chemistry
sec-e
ch-8
d-and-f-block-elements
asked
Oct 18, 2016
by
meena.p
1
answer
Account for the following : (i) Transition elements show highest oxidation state in their oxides thanfluorides. (ii) Cu has positive electrode potential in the first transition series. (iii) Ionisation enthalpy of lanthanides is higher than actinides. (iv) Potassium dichromate is a good oxidising agent in acidic medium. (v) Actinides show more number of oxidation states than lanthanides.
cbse
class12
chemistry
sec-e
ch-4
chemical-kinetics
asked
Oct 18, 2016
by
meena.p
1
answer
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