Recent questions tagged medium

The radiation corresponding to $3 \to 2$ transition of hydrogen atom falls on a metal surface to produce photoelectrons. These electrons are made to enter a magentic field of $3 \times 10^{-4}T$ . If the radius of the largest circular path followed by these electrons is $10.0\; mm$, the work function of the metal is close to :

asked Apr 7, 2014 by meena.p

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Among the following oxoacids, the correct decreasing order of acid strength is

asked Apr 7, 2014 by sreemathi.v

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Hydrogen $\bigg( _1H^1\bigg)$, Deuterium $\bigg(_1H^2 \bigg)$, singly ionised Helium $\bigg(_2He^{4}\bigg)^+$ and doubly ionised . Consider an electron transition from $n = 2$ to $n = 1$. If the wave lengths of emitted radiation are $\lambda _1, \lambda_2, \lambda_3\;and \;\lambda_4$ respectively then approximately which one of the following is correct?

asked Apr 7, 2014 by meena.p

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Which one is classified as a condensation polymer?

asked Apr 7, 2014 by sreemathi.v

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The ratio of masses of oxygen and nitrogen in a particular gaseous mixture is 1 : 4. The ratio of number of their molecules is

asked Apr 7, 2014 by sreemathi.v

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A green light is incident from the water to the air-water interface at the critical angle $(\theta)$ . Select the correct statement

asked Apr 7, 2014 by meena.p

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Given below are the half - cell reactions\begin{array}{1 1}Mn^{2+}+2e^-\rightarrow Mn;E^{\large\circ}=-1.18V\\2(MN^{3+}+e^-\rightarrow Mn^{2+});E^{\large\circ}=-1.18V\end{array}The $E^{\large\circ}$ for $3Mn^{2+}\rightarrow Mn+2Mn^{3+}$ will be

asked Apr 7, 2014 by sreemathi.v

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The major organic compound formed by the reaction of 1, 1, 1 - trichloroethane with silver powder is

asked Apr 7, 2014 by sreemathi.v

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The correct set of four quantum numbers for the value electrons of rubidium atom (Z = 37) is

asked Apr 7, 2014 by sreemathi.v

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There is a circular tube in a vertical plane. Two liquids which do not mix and of densities $d_1$ and $d_2$ are filled int hetube. Each liquid subtends $90^{\circ}$ angle at centre. Radius joining there interface makes an angle $\alpha$ with vertical. Ratio $\large\frac{d_1}{d_2}$ is

asked Apr 7, 2014 by meena.p

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A pipe of length $85\;cm$ is closed from one end. Find the number of possible natural oscillations of air column in the pipe whose frequencies lie below $1250\; Hz$. The velocity of sound in air is $340\; m/s$.

asked Apr 7, 2014 by meena.p

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Which one of the following base is not present in DNA?

asked Apr 7, 2014 by sreemathi.v

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Three rods of Copper, Brass and Steel are welded together to form a $Y$- shaped structure. Area of cross -section of each rod $= 4 cm^2$. End of copper rod is maintained at $10^{\circ}C$.Lengths of the copper, brass and steel rods are $46, 13 \;and \;12\; cms$ respectively. The rods are thermally insulated from surroundings except at ends. Thermal conductivies of copper, brass and steel are $0.92, 0.26\; and\; 0.12$ CGS units respectively. Rate of heat flow through copper rod is

asked Apr 7, 2014 by meena.p

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Consider the basic strength of amines in aqueous solution,which one has the smallest $pK_b$ value?

asked Apr 7, 2014 by sreemathi.v

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A thin convex lens made from crown glass $\bigg(\mu=\large\frac{3}{2}\bigg)$ has focal length $f.$When it is measured in two different liquids having refractive indices $\large\frac{4}{3}$ and $\large\frac{5}{3}$, it has the focal lengths $f_1$ and $f_2$ respectively. The correct relation between the focal lengths is

asked Apr 7, 2014 by meena.p

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Which series of reactions correctly respensents chemical relations related to iron and its compound?

asked Apr 7, 2014 by sreemathi.v

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From a tower of height $H$, a particle is thrown vertically upwards with a speed $u$. The time taken by the particles, to hit the ground, is n times that taken by it to reach the highest point of its path. The relation between $H, u\; and\; n$ is

asked Apr 7, 2014 by meena.p

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For the non- stoichiometre reaction 2A + B $\rightarrow$ C + D , the following kinetic data were obtained in three separate experiments, all at 298 K.

asked Apr 7, 2014 by sreemathi.v

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One mole of diatomic ideal gas undergoes a cyclic process $ABC$ as shown in figure. The process $BC$ is adiabatic. The temperatures at $A, B\; and\; C$ are $400 K,800 K\; and\; 600 K$ respectively. Choose the correct statement.

asked Apr 7, 2014 by meena.p

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For which of the following molecule/s significant $\mu\neq 0$?

asked Apr 7, 2014 by sreemathi.v

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A mass $m$ is supported by a massless string wound around a uniform hollow cylinder of mass $m$ and radius $R$. If the string does not slip on the cylinder, with what acceleration will the mass fall on release?

asked Apr 7, 2014 by meena.p

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The equation which is balanced and represents the correct product(s) is

asked Apr 7, 2014 by sreemathi.v

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In the circuit shown here, the point $C$ is kept connected to point $A$ till the current flowing through the circuit becomes constant. Afterward, suddenly, point $C$ is disconnected from point $A$ and connected to point $B$ at time $t = 0.$ Ratio of the voltage across resistance and the inductor at $t = \large\frac{L}{R}$ will be equal to

asked Apr 7, 2014 by meena.p

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The correct statement for the molecule, $CsI_3$ is

asked Apr 7, 2014 by sreemathi.v

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During the propagation of electromagnetic waves in a medium

asked Apr 7, 2014 by meena.p

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On heating an aliphatic primary amine with chlooroform and ethanolic potassium hydroxide, the organic compound formed is:

asked Apr 7, 2014 by sreemathi.v

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The forward biased diode connection is

asked Apr 7, 2014 by meena.p

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Sodium phenoxide when heated with $CO_2$ under pressure at $125^{\large\circ}C$ yields a product which on the acetylation produces $C$.The major product $C$ would be:

asked Apr 7, 2014 by sreemathi.v

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The coercivity of a small magnet where the ferromagnet gets demagnetized is $3 \times10^3\;Am^{-1}$. The current required to a passed in a solenoid of length $10\; cm$ and number of turns $100$, so that the magnet gets demagnetized when inside the solenoid, is

asked Apr 7, 2014 by meena.p

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A particles moves with simple harmonic motion in a straight line. In first ${\tau} {s}$ after starting fromrest it travels a distance $a$, and in next ${\tau} {s}$ in travels $2a$ in same direction, then

asked Apr 7, 2014 by meena.p

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In the reaction,$CH_3COOH\quad\underrightarrow{LiAlH_4}\quad A\quad\underrightarrow{PCl_5}\quad B\quad\underrightarrow {Alc.KOH}\quad C$,the product C is

asked Apr 7, 2014 by sreemathi.v

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In a large building, there are $15$ bulbs of $40 \;W$, $5$ bulbs of $100\; W$, $5$ fans of $80\; W$ and 1 heater of $1\; kW$. The voltage of the electric mains is $220\; V$. The minimum capacity of the main fuse of the building will be

asked Apr 7, 2014 by meena.p

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For the rection $SO_2(g)+\large\frac{1}{2}$$O_2(g)\leftrightharpoons SO_3(g)$ if $K_P = K_C (RT)^X$ where the symbols have usual meaning then the value of x is: (assuming ideality)

asked Apr 7, 2014 by sreemathi.v

1 answer

The density of a pure substance 'A' whose atoms pack in cubic close pack arrangement is 1g m/cc . If B atoms can occupy tetrahedral voids and all the tetrahedral voids are occupied by 'B' atoms what is the density of resulting solid in gm/cc . [Atomic mass (A) = 30 gm/mol and atomic mass (B) = 50gm/mol]

asked Apr 7, 2014 by sharmaaparna1

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Four particles, each of mass M and equidistant from each other, move along a circle of radius R under the action of their mutual gravitational attraction. The speed of each particle is

asked Apr 7, 2014 by meena.p

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The equivalent conductance of NaCl at concentration C and at infinite dilution are $\lambda_C$ and $\lambda_{\infty}$ respectively.The correct relationship between $\lambda_C$ and $\lambda_{\infty}$ is given as : (where the constant B is positive)

asked Apr 7, 2014 by sreemathi.v

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A student measured the length of a rod and wrote it as $3.50\; cm$.What instrument did he use to measure it?

asked Apr 7, 2014 by meena.p

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For the estimation of nitrogen, 1.4 g of an organic compound was digested by Kjeldahl method and the evolved ammonia was absorbed in 60 mL of $\large\frac{M}{10}$ sulphuric acid.The unreacted acid required 20 mL of $\large\frac{M}{10}$ sodiumhydroxideforcompleteneutralization.The percentage of nitrogen in the compound is:

asked Apr 7, 2014 by sreemathi.v

1 answer

The octahedral complex of a metal ion $M^{3+}$ with four monodentate ligands $L_1, L_2 , L_3$ and $L_4$ absorb wavelengths in the region of red, green, yellow and blue, respectively. The increasing order of ligand strength of the four ligands are

asked Apr 7, 2014 by sreemathi.v

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A parallel plate capacitor is made of two circular plates separated by a distance of $5mm$ and with a dielectric of dielectric constant $2.2$ between them. When the electric field in the dielectric is $ 3 \times 10^4 \;V/m$, the change density of the positive plate will be close to

asked Apr 7, 2014 by meena.p

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In $SN_ 2$ reaction, the correct order of reactivity for the following compounds:$CH_3Cl,CH_3CH_2Cl,(CH_3)_2CHCl$ and $(CH_3)_3CCl$ is

asked Apr 7, 2014 by sreemathi.v

1 answer

Match List- I (Electromagnetic wave type) with List-II (Its association/application) and select the correct option from the choices given below the lists :

asked Apr 7, 2014 by meena.p

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In which of the following reactions $H_2O_2$ acts as a reducing agent ?

asked Apr 7, 2014 by sreemathi.v

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Consider separate solutions of $0.500\; M$ $C_2 H_5 OH (aq),0.100M $$Mg_3(PO_4)_2(aq),0.250M KBr(aq)$ and $0.125\; M$ $Na_3PO_4(aq)$ at $25^{\large\circ}C$.Which Which statement is true about these solutions, assuming all salts to be strong electrolytes ?

asked Apr 7, 2014 by sreemathi.v

1 answer

An open glass tube is immersed in mercury in such a way that a length of $8\; cm$ extends above the mercury level. The open end of the tube is then closed and sealed and the tube is raised vertically up by additional $46\; cm$. What will be length of the air column above mercury in the tube now? (Atmospheric pressure = $76\; cm$ of Hg)

asked Apr 7, 2014 by meena.p

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CsCl crystallises in body centred cubic lattice. If 'a' is its edge length then which of the following expressions is correct ?

asked Apr 7, 2014 by sreemathi.v

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The current voltage relation of diode is given by $I= (e^{1000 V/T } -1)mA$, where the applied voltage V is in volts and the temperature $T$ is in degree kelvin. If a students makes an error measuring $\pm 0.01\;V$ while measuring the current of $5\;mA$ at $300\;K$, what will be error in the value of current in $mA?$

asked Apr 7, 2014 by meena.p

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A bob of mass $m$ attached to an inextensible string of length $l$ is suspended from a vertical support. The bob rotates in a horizontal circle with an angular speed $\omega\; rad/s$ about the vertical. About the point of suspension

asked Apr 7, 2014 by meena.p

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Resistance of $0.2\; M$ solution of an electrolyte is $50 \Omega$ . The specific conductance of the solution is $1.4 \;m^{-1}$ . The resistance of $0.5\; M$ solution of the same electrolyte is $280\Omega$ .The molar conductivity of $0.5\;M$ solution of the electrolyte in $S m^2mol^{-1}$ is :

asked Apr 7, 2014 by sreemathi.v

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A conductor lies along the $z$-axis at $-1.5 \leq z \leq 1.5\;m $ and carries a fixed current of $10.0\;A$ in $-a_{z}$ direction (see figure). For a field $\bar{B}=3.0 \times 10^{-4} e^{-0.2x} \hat a_y\;T$. Find the power required to move the conductor at constant speed to $x = 2.0m, y = 0\;m\;in\; 5 \times 10–3\; s$. Assume parallel motion along the $x$-axis.

asked Apr 7, 2014 by meena.p

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