Recent questions in 2012

The population $p(t)$ at time $t$ of a certain mouse species satisfies the differential equation $\frac{dp(t)}{dt} = 0.5\; p(t) -450$. If $p(0) = 850$, then the time at which the population becomes zero is

asked Dec 11, 2018 by pady_1

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In the given transformation, which of the following is the most appropriate reagent ?

asked Dec 11, 2018 by pady_1

1 answer

In which of the following pairs the two species are not isostructural ?

asked Dec 11, 2018 by pady_1

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Iodoform can be prepared from all except :

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2-Hexyne gives trans-2-Hexene on treatment with :

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The increasing order of he ionic radii of the given isoelectronic species is :

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What is DDT among the following :

asked Dec 11, 2018 by pady_1

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$K_f$ for water is $1.86 \;K\;mol^{-1}$. If your automobile radiator holds 1.0 kg of water, how many grams of ethylene glycol $(C_2H_6O_2)$ must you add to get the freezing point of the solution lowered to $-2.8^{\circ}C$ ?

asked Dec 11, 2018 by pady_1

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Which branched chain isomer of the hydrocarbon with molecular mass 72 u gives only one isomer of mono substituted alky halide ?

asked Dec 11, 2018 by pady_1

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The pH of a 0.1 molar solution of the acid HQ is 3. The value of the ionization constant, Ka of this acid is :

asked Dec 11, 2018 by pady_1

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Iron exhibits +2 and +3 oxidation states. Which of the following statements about iron is incorrect ?

asked Dec 11, 2018 by pady_1

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For a first order reaction, $(A) \to products$, the concentration of A changes from 0.1 M to 0.025 M in 40 minutes. The rate of reaction when the concentration of A is 0.01 M is :

asked Dec 11, 2018 by pady_1

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The electrons identified by quantum numbers n and I : (a) n = 4, I = 1 (b) n = 4, I = 0 (c) n = 3, I = 2 (d) n = 3, I = 1 Can be placced in order of increasing energy as :

asked Dec 11, 2018 by pady_1

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Very pure hydrogen (99.9%) can be made by which of the following processes ?

asked Dec 11, 2018 by pady_1

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How many chiral compounds are possible on monochlorination of 2-methyl butane ?

asked Dec 11, 2018 by pady_1

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Ortho-Nitrophenol is less soluble in water than p- and m- Nitrophenols because :

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Aspirin is known as :

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Which one of the following statements is correct ?

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The compressibility factor for a real gas at high pressure is :

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The equilibrium constant $(K_C)$ for the reaction $N_2(g) + O_2(g) \to 2NO (g)$ at temperature T is $ 4 \times 10^{-4}$. The value of $K_C$ for the reaction, $NO(g) \to 1/2 N_2 (g) + 1/2 O_2 (g)$ at the same temperature is :

asked Dec 11, 2018 by pady_1

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According toFreundiich adsorption isotherm, which of the following is correct ?

asked Dec 11, 2018 by pady_1

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The standard reduction potentials for $Zn^{2+}/Zn, Ni^{2+}/Ni$ and $Fe^{2+}/Fe$ are -0.76, -0.23 and -0.44V respectively. The reaction $X + Y^2 \to X^{2+} + Y$ will be spontaneous when :

asked Dec 11, 2018 by pady_1

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Which of the following on thermal decomposition yields a basic as well as an acidic oxide ?

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The species which can best serve as an initiator for the cationic polymerization is :

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The density of a solution prepared by dissolving 120 g of urea ( mol. Mass = 60 u) in 1000 g of water is 1.15 g/mL. The molarity of this solution is :

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The incorrect expression among the following is :

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Which of the following compounds can be detected by Molisch's test ?

asked Dec 11, 2018 by pady_1

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The molecule having smallest bond angle is :

asked Dec 11, 2018 by pady_1

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Lithium forms body centred cubic structure. The length of the side of its unit cell is 351 pm. Atomic radius of the lithium will be :

asked Dec 11, 2018 by pady_1

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Which method of purification is represented by the following equation : $Ti(s) + 2I_2 (g) \xrightarrow{523 K} TiI_4 (g) \xrightarrow{1700 K} Ti(s) + 2I_2 (g)$

asked Dec 11, 2018 by pady_1

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Which among he following will be named as dibromidobis (ethylene diamine) chrominum (III) bromide ?

asked Dec 11, 2018 by pady_1

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Proton, Deuteron and alpha particle of the same kinetic energy are moving in circular trajectories in a constant magnetic field. The radii of proton, deuteron and alpha particle are respecctively $r_p$, $r_d$ and $r_{\alpha}$. Which one of the following relations is correct ?

asked Dec 11, 2018 by pady_1

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This question has statement 1 and statement 2. Of the four choices given after the statements, choose the one that best describes the two statements. An insulating solid sphere of radius R has a uniformly positive charge density $\rho$. As a result of this uniform charge distribution there is a finite value of electric potential at the centre of the sphere, at the surface of the sphere and also at a point out side the sphere. The electric potential at infinity is zero. Statement 1 : When a charge q is taken from the centre to the surface of the sphere, its potential energy changes by $\frac{qp}{3 \varepsilon_0}$ Statement 2 : The electric field at a distance r (r < R) from the centre of the sphere is $\frac{\rho r}{ 3 \varepsilon_0}$

asked Dec 11, 2018 by pady_1

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A spectrometer gives the following reading when used to measure the angle of a prism. Main scale reading : 58.5 degree Vernier scale reading : 09 divisions Given that 1 division on main scale corresponds to 0.5 degree. Total divisions on the vernier scale is 30 and match with 29 divisions of the main scale. The angle of the prism from the above data

asked Dec 11, 2018 by pady_1

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A diatomic molecule is made of two masses $m_1$ and $m_2$ which are separated by a distance $r$. If we calculate its rotational energy by applying Bohr's rule of angular momentum quantization, its energy will be given by (n is an integer)

asked Dec 11, 2018 by pady_1

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An object 2.4 m in front of a lens forms a sharp image on a film 12 cm behind the lens. A glass plate 1 cm thick, of refractive index 1.50 is interposed between lens and film with its plane faces parallel to film. At what distance (from lens) should object be shifted to be in sharp focus on film ?

asked Dec 11, 2018 by pady_1

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A cylindrical tube, open at both ends, has a fundamental frequency, f, in air. The tube is dipped vertically in water so that half of it is in water. The fundamental frequency of the air-column is now

asked Dec 11, 2018 by pady_1

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Two cars of masses $m_1$ and $m_2$ are moving in circles of radii $r_1$ and $r_2$, respectively. Their speeds are such that they make complete circles in the same times t. The ratio of their centripetal acceleration is

asked Dec 11, 2018 by pady_1

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This question has statement 1 and statement 2. Of the four choices given after the statements, choose the one that best describes the two statements If two springs $S_1$ and $S_2$ of force constants $k_1$ and $k_2$, respectively, are stretched by the same force, it is found that more work is done on spring $S_1$ than on spring $S_2$. If stretched by the same amount, work done on $S_1$, will be more than that on $S_2$. Statement 2 : $k_1 < k_2$.

asked Dec 11, 2018 by pady_1

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A Carnot engine, whose efficiency is 40%, takes in heat from a source maintained at a temperature of 500 K. It is desired to have an engine of efficiency 60%. Then, the intake temperature for the same exhaust (sink) temperature must be

asked Dec 11, 2018 by pady_1

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Assume that a neutron breaks into a proton and an electron. The energy released during this process is (Mass of neutron = $1.6725 \times 10^{-27}\;kg$; mass of proton = $1.6725 \times 10^{-27} \;kg$ mass of electron = $9 \times 10^{-31}\; kg $)

asked Dec 11, 2018 by pady_1

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A radar has a power of 1 Kw and is operating at a frequency of 10 GHz. It is located on a mountain top of height 500 m. The maximum distance upto which it can detect object located on the surface of the earth (Radius of earth = $6.4 \times 10^{6} m$ ) is

asked Dec 11, 2018 by pady_1

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Truth table for system of four NAND gates as shown in figure is

asked Dec 11, 2018 by pady_1

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A charge Q is uniformly distributed over the surface of non conducting disc of radius R. The disc rotates about an axis perpendicular to its plane and passing through its centre with an angular velocity $\omega$. As a result of this rotation a magnetic field of induction B is obtained at the centre of the disc. If we keep both the amount of charge placed on the disc and its angular velocity of be constant and vary the radius of the disc then the variation of the magnetic induction at the centre of the disc will be represented by the figure

asked Dec 11, 2018 by pady_1

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A thin liquid film formed between a U-shaped wire and a light slider supports a weight of $1.5 \times 10^{-2}N$ (see figure). The length of the slider is 30 cm and its weight negligible. The surface tension of the liquid film is

asked Dec 11, 2018 by pady_1

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This question has statement 1 and statement 2. Of the four choices given after the statements, choose the one that best describes the two statements Statement 1 : Davisson-germer experiment established the wave nature of electrons. Statement 2 : If electrons have wave nature, they can interfere and show diffraction.

asked Dec 11, 2018 by pady_1

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A boy can throw a stone up to a maximum height of 10 m. The maximum horizontal distance that the boy can throw the same stone up to will be

asked Dec 11, 2018 by pady_1

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Resistance of a given wire is obtained by measuring the current flowing in it and the voltage difference applied across it. If the percentage errors in the measurement of the current and the voltage difference are 3% each, then error in the value of resistance of the wire is

asked Dec 11, 2018 by pady_1

1 answer

Two electric bulbs marked 25 W - 220 V and 100 W - 220 V are connected in series to a 440 V supply. Which of the bulbs will fuse ?

asked Dec 11, 2018 by pady_1

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A particle of mass m is at rest at the origin at time t=0. It is subjected to a force $F(t) = F_0e^{-bt}$ in the $x$ direction. Its speed v(t) is depicted by which of the following curves ?

asked Dec 11, 2018 by pady_1

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