Recent questions tagged set a

The Sum of first 9 terms of the series $\large\frac{1^3}{1} +\frac{1^3+2^3}{1+3} +\frac{1^3+2^3+3^3}{1+3+5}+....$ is

asked Oct 15, 2015 by meena.p

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If $m$ is the A.M of two distinct real numbers $l$ and $n (l ,n > 1) $ and $G_1,G_2$ and $G_3$ are three geometric means between l and n, then $G_1^4 +2 G_2^4+G_3^4 $ equals

asked Oct 15, 2015 by meena.p

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The sum of coefficient of integral powers of x in the binomial expansion of $(1-2 \sqrt x)^{50}$ is :

asked Oct 15, 2015 by meena.p

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The number of integers greater than $6,000$ than can be formed, using the digits $3,5,6,7$ and $8$ without repetition, is :

asked Oct 15, 2015 by meena.p

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The set of all values of $\lambda$ for which the system of linear equations : $2x_1 -2x_2+x_3 =\lambda x_1 ; 2x_1 -3x_2+2x_3 =\lambda x_2 ; -x_1 +2x_2 =\lambda x_3 $ has a non- trivial solution ,

asked Oct 15, 2015 by meena.p

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If $A= \begin{bmatrix}1 & 2 & 2\\ 2 & 1 & -2\\ a & 2 & b \end{bmatrix}$ is a matrix satisfying the equation $AA^T=9I$, where I is $3 \times 3 $ identify matrix , then the ordered pair $(a,b)$ is equal to :

asked Oct 15, 2015 by meena.p

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Let $ \alpha$ and $\beta$ be the roots of equation $x^2-6x-2=0$. If $a_n= \alpha^n-\beta^n $, for $n \geq 1$, then the value of $ \large\frac{a_{10}-a_{a8}}{2a_g}$ is equal to :

asked Oct 14, 2015 by meena.p

1 answer

A complex number z is said to be unimodular if $|z|=1$ .Suppose $z_1$ and $z_2$ are complex number Such that $ \large\frac{z_1 -2 z_2}{2-z_1z_2}$is unimodular and $z_2$ is not unimodular . Then the point $Z_1$ lies on a :

asked Oct 14, 2015 by meena.p

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Let A and B two set containing four and two elements respectively . Then the number of subsets of the set $A \times B$ , each having at least three elements is :

asked Oct 14, 2015 by meena.p

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Which of the following compounds is not colored yellow ?

asked Oct 14, 2015 by meena.p

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Which of the following compounds is not an antacid ?

asked Oct 14, 2015 by meena.p

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Which of the vitamins given below is water soluble ?

asked Oct 14, 2015 by meena.p

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Which polymer is used in the manufacture of paints and lacquers ?

asked Oct 14, 2015 by meena.p

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In the reaction

asked Oct 14, 2015 by meena.p

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In the reaction

asked Oct 14, 2015 by meena.p

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In the following sequence of reactions : Find the product of C is :

asked Oct 14, 2015 by meena.p

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The synthesis of alkyl fluorides is best accomplished by :

asked Oct 14, 2015 by meena.p

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Which compound would give 5- keto -2- methyl hexanal upon oznolysis ?

asked Oct 14, 2015 by meena.p

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Which of the following compounds will exhibit geometrical isomerism ?

asked Oct 14, 2015 by meena.p

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In Carius method of estimation of halogens, $250\;mg$ of an organic compound gave $141\;mg$ of $AgBr$. The percentage of bromine in the compound is

asked Oct 14, 2015 by meena.p

1 answer

Assertion : Nitrogen and oxygen are the main components in the atmosphere but these do not react to form oxides of nitrogen . Reason : The reaction between nitrogen and oxygen requires high temperature .

asked Oct 14, 2015 by meena.p

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The color of $KMnO_4$ is due to :

asked Oct 14, 2015 by meena.p

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The number of geometric isomers that can exist for square planar $[Pt(Cl)(py)(NH_3)(NH_2OH)] +$ (py= pyridine ):

asked Oct 14, 2015 by meena.p

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Which one has the highest boiling point ?

asked Oct 13, 2015 by meena.p

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Match the catalysts to the correct processes :

asked Oct 13, 2015 by meena.p

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Which one of the following alkaline earth metal sulphates has its hydration enthalpy greater than its lattice enthalpy ?

asked Oct 13, 2015 by meena.p

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Which among the following is the most reactive ?

asked Oct 13, 2015 by meena.p

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From the following statements regarding $H_2O_2$ , choose the incorrect statement :

asked Oct 13, 2015 by meena.p

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In the context of the Hall -Hero ult process for the extraction of Al, which of the following statement is false ?

asked Oct 13, 2015 by meena.p

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The ionic radii (in A) of $NH^{3-},O^{2-}$ and $F^{-}$ are respectively:

asked Oct 13, 2015 by meena.p

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$3\;g$ of activated charcoal was added to $50\;mL$ of acetic acid solution $(0.06\;N)$ in a flask. After an hour it was filtered and strength of the filtrate was found to be $0.042\;N$ . the amount of acetic acid absorbed (per gram of charcoal) is :

asked Oct 13, 2015 by meena.p

1 answer

Higher order $(>3)$ reactions are rare due to :

asked Oct 13, 2015 by meena.p

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Two Faraday of electricity is passed through a solution of $CuSO_4$ . The mass of copper deposited at the cathode is : (at .mass of $Cu=63.5\;amu)$

asked Oct 13, 2015 by meena.p

1 answer

The standard Gibbs energy change at 300 K for the reaction $2A \rightleftharpoons B +C$ is $2494.2J$ . At a given time, the composition of the reaction mixture is $[A]= \frac{1}{2}, [B]=2$ and $ [C]=\frac{1}{2}$. The reaction proceeds in the : $[R= 8.314\;J/K/mol,e=2.718]$

asked Oct 13, 2015 by meena.p

1 answer

The vapour pressures of acetone at $ 20^{\circ}$ is $185$ torr . When $1.2 g $ of a non- volatile substance was dissolved in 100 g of acetone at $20^{\circ}$,ITS Vapour pressure was $183$ torr. The molar mass $(g mol^{-1})$ of the substance is :

asked Oct 13, 2015 by meena.p

1 answer

The following reaction is performed at $298 \;K$ $2NO(g) +O_2(g) \rightleftharpoons 2NO_2(g)$ . The standard free energy of formation of $NO(g)$ is $86.6\;kJ/mol$ at $298\;K$. What is the standard free energy of formation of $NO_2(g) $ at $298\;K?$

asked Oct 13, 2015 by meena.p

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The inter molecular interaction that is dependent on the inverse cube of distance between the molecules is :

asked Oct 13, 2015 by meena.p

2 answers

Which of the following is the energy of a possible excited state of hydrogen ?

asked Oct 13, 2015 by meena.p

1 answer

Sodium metal crystallizes in a body centred cubic lattice with a unit cell edge of $ 4.29 \mathring{A}$. The radius of sodium atom is approximately :

asked Oct 13, 2015 by meena.p

1 answer

The molecular formula of a commercial resin used for exchanging ions in water softening is $C_8H_7SO_3Na$ (Mol.wt.206)What would be the maximum uptake of $Ca^{2+}$ ions by the resin when expressed in mole per gram resin ?

asked Oct 13, 2015 by meena.p

1 answer

An LCR circuit is equivalent to a damped pendulum. In an LCR circuit the capacitor is charged to $Q_0$ and then connected to the L and R as shown below : If a student plots graphs of the square of maximum charge $(Q^2_{max})$ on the capacitor with time(t) for two different values $L_1$ and $L_2(L_1 > L_2)$ of L then which of the following represents this graph correctly ?

asked Oct 13, 2015 by meena.p

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A signal of 5 kHz frequency is amplitude modulated on a carrier wave of frequency 2 MHz. The frequencies of the resultant signal is /are :

asked Oct 13, 2015 by meena.p

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Match list -I (Fundamental experiment) with List - II (its conclusion ) and select the correct option from the choices given below the list :

asked Oct 13, 2015 by meena.p

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As an electron makes a transition from an excited state to the ground state of a hydrogen - like atom / ion :

asked Oct 13, 2015 by meena.p

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Assuming human pupil to have a radius of $0.25\;cm$ and a comfortable viewing distance of $25\;cm$ , the minimum separation between two objects that human eye can resolve at 500 nm wavelength is :

asked Oct 13, 2015 by meena.p

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On a hot summer night, the refractive index of air is smallest near the ground and increases with height from the ground. When a light beam is directed horizontally,the Huygen's principle leads us to conclude that as it travels , the light beam

asked Oct 12, 2015 by meena.p

1 answer

Monochromatic light is incident on a glass prism of angle A. If the refractive index of the material of the prism is $ \mu$, a ray, incident at an angle $\theta$ , on the face $AC$ of the prism provided:

asked Oct 12, 2015 by meena.p

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A red LED emits light at $0.1$ watt uniformly around it. The amplitude of the electric field of the light at a distance of $1m$ from the diode is

asked Oct 12, 2015 by meena.p

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An inductor $(L=0.03H)$ and a resistor $(R= 0.15\;k\Omega)$ are connected in series to battery of $15\;V\;EMF$ in a circuit shown below. The key $K_1$ has been kept closed below. . The key kept closed for a long time. Then at $ t=0$, $K_1$ is opened and the key $K_2$ is closed simultaneously . At $t= 1\;ms$ , the current in the circuit will be : $(e^5 \approx 150)$

asked Oct 12, 2015 by meena.p

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A rectangular loop of sides 10 cm and 5 cm carrying a current 1 of 12 A is placed in different orientations as shown in the figures below : If there is a uniform magnetic field of $0.3 \;T$ in the positive Z direction , in which orientations the loop would be in (i) stable equilibrium and (ii) unstable equilibrium ?

asked Oct 12, 2015 by meena.p

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