Recent questions tagged 2010

The binding energy per nucleon for the parent nucleus is $E_1$ and that for the daughter nuclei is $E_2$.Then

asked Dec 11, 2018 by pady_1

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The figure shows the position â€“ time (x â€“ t) graph of one-dimensional motion of a body of mass 0.4 kg. The magnitude of each impulse is

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In the circuit shown below, the key K is closed at t = 0. The current through the battery is

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Two long parallel wires are at a distance 2d apart. They carry steady equal current flowing out of the plane of the paper as shown. The variation of the magnetic field along the line XX ' is given by

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A particle is moving with velocity $v = K(y \hat i + x \hat j) $, where K is a constant. The general equation for its path is

asked Dec 11, 2018 by pady_1

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A ball is made of a material of density $\rho$ where $\rho_{oil} < \rho < \rho_{water}$ with $\rho_{oil}$ and $\rho_{water}$ representing the densities of oil and water, respectively. The oil and water are immiscible. If the above ball is in equilibrium in a mixture of this oil and water, which of the following pictures represents its equilibrium position ?

asked Dec 11, 2018 by pady_1

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Statement-1 : When ultraviolet light is incident on a photocell, its stopping potential is $V_0$ and the maximum kinetic energy of the photoelectrons is $K_{max}$. When the ultraviolet light is replaced by X- rays, both V0 and Kmax increase. Statement-2 : Photoelectrons are emitted with speeds ranging from zero to a maximum value because of the range of frequencies present in the incident light.

asked Dec 11, 2018 by pady_1

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Statement-1 : Two particles moving in the same direction do not lose all their energy in a completely inelastic collision. Statement-2 : Principle of conservation of momentum holds true for all kinds of collisions.

asked Dec 11, 2018 by pady_1

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Let C be the capacitance of a capacitor discharging through a resistor R. Suppose $t_1$ is the time taken for the energy stored in the capacitor to reduce to half its initial value and $t_2$ is the time taken for the charge to reduce to one-fourth its initial value. Then the ratio $t_1/t_2$ will be

asked Dec 11, 2018 by pady_1

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A rectangular loop has a sliding connector PQ of length A and resistance $R \Omega$ and it is moving with a speed v as shown. The set-up is placed in a uniform magnetic field going into the plane of the paper. The three currents $I_1, I_2$ and I are

asked Dec 11, 2018 by pady_1

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For a particular reversible reaction at temperature $T, \Delta H$ and $\Delta S$ were found to be both +ve. If Te is the temperature at equilibrium, the reaction would be spontaneous when

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The polymer containing strong intermolecular forces e.g. hydrogen bonding,

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The correct order of $E^0_{M^2/M}$ values with negative sign for the four successive elements $Cr,Mn,Fe$

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Biuret test is not given by

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Out of the following, the alkene that exhibits optical isomerism is

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Percentage of free space in cubic close packed structure and in body centred packed structure are respectively

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At $25^{\circ}C$, the solubility product of $Mg(OH)_2$ is $1.0 \times 10^{–11}$. At which $pH$, will $Mg^{2+}$ ions start precipitating in the form of $Mg(OH)_2$ from a solution of $0.001\; M \;Mg^{2+}$ ions ?

asked Dec 11, 2018 by pady_1

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The Gibbs energy for the decomposition of $Al_2O_3$ at $500^{\circ}C$ is as follows : $\large\frac{2}{3}$$Al_2O_3 \to \large\frac{4}{3}$$Al+O_2, \Delta_rG=+966\;kJ\;mol^{-1}$ The potential difference needed for electrolytic reduction of $Al_2O_3$ at $500^{\circ}C$ is at least

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Solubility product of silver bromide is $5.0 \times 10^{–13}$. The quantity of potassium bromide (molar mass taken as $120 \;g \;of\; mol^{–1}$) to be added to $1 \;litre\; of\; 0.05\; M$ solution of silver nitrate to start the precipitation of AgBr is

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The correct sequence which shows decreasing order of the ionic radii of the elements is

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The correct order of increasing basicity of the given conjugate bases $(R = CH_3)$ is

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The edge length of a face centered cubic cell of an ionic substance is 508 pm. If the radius of the cation is 110 pm, the radius of the anion is

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In aqueous solution the ionization constants for carbonic acid area $K_1=4.2 \times 10^{-}$ and $K_2=4.8 \times 10^{-11}$ Select the correct statement for a saturated 0.034 M solution of the carbonic acid.

asked Dec 11, 2018 by pady_1

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Three reactions involving $H_2 PO_4^{-}$ are given below :$(i)H_3PO_4+H_2O \to H_3O^{+} +H_2PO_4^{-} \qquad (ii) H_2PO_4^{-}+H_2O \to HPO_4^{2-}+H_3O^{+} \qquad (iii)H_2PO_4^{-}+OH^{-} \to H_3PO_4+O^{2-}$ In which of the above does $H_2PO_4^{-}$ act as an acid ?

asked Dec 11, 2018 by pady_1

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The main product of the following reaction is $C_6H_5CH_2CH(OH)CH(CH_3)_2 \qquad \underrightarrow{\qquad conc.H_2SO_4 \qquad} \qquad ?$

asked Dec 11, 2018 by pady_1

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On mixing, heptane and octane form an ideal solution. At $373\; K$, the vapour pressures of the two liquid components (heptane and octane) are $105\; k\;Pa$ and $45\; k\;Pa$ respectively. Vapour pressure of the solution obtained by mixing $25.0\;g$ of heptane and $35\; g$ of octane will be (molar mass of heptane = $100 g\; mol^{–1}$ an dof octane $= 114\; g\; mol^{–1}).$

asked Dec 11, 2018 by pady_1

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Which one of the following has an optical isomer ?

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Consider the following bromides : The correct order of $S_N1$0 reactivity is

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Ionisation energy of $He^{+}$ is $19.6 \times 10^{–18}\; J \;atom^{–1}.$ The energy of the first stationary state $(n = 1)$ of $Li^{2+}$ is

asked Dec 11, 2018 by pady_1

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The energy required to break one mole of Cl–Cl bonds in $Cl_2$ is $242 \;kJ\; mol^{–1}$. The longest wavelength of light capable of breaking a single $Cl – Cl$ bond is $(c = 3 x 10^8 ms^{–1} \;and\; NA = 6.02 \times 10^{23} mol^{–1})$

asked Dec 11, 2018 by pady_1

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$29.5\; mg$ of an organic compound containing nitrogen was digested according to Kjeldahl’s method and the evolved ammonia was absorbed in $20\; mL$ of $0.1\; M\; HCl$ solution. The excess of the acid required $15\; mL$ of $0.1\; M \;NaOH$ solution for complete neutralization. The percentage of nitrogen in the compound is

asked Dec 11, 2018 by pady_1

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In the chemical reactions, the compounds ‘A’ and ‘B’ respectively are

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From amongst the following alcohols the one that would react fastest with conc. $HCl$ and anhydrous $ZnCl_2$, is

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If sodium sulphate is considered to be completely dissociated into cations and anions in aqueous solution, the change in freezing point of water ($\Delta T_f$), when 0.01 mol of sodium sulphate is dissolved in 1 kg of water, is $(K_f = 1.86\; K\; kg\; mol^{–1})$

asked Dec 11, 2018 by pady_1

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One mole of a symmetrical alkene on ozonolysis gives two moles of an aldehyde having a molecular mass of $44\; u$. The alkene is

asked Dec 11, 2018 by pady_1

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If $10^{–4 }dm^3$ of water is introduced into a $1.0\; dm^{3}$ flask to 300 K, how many moles of water are in the vapour phase when equilibrium is established ? (Given : Vapour pressure of $H_2O$ at $300\; K$ is $3170 \;Pa ; R = 8.314 J K^{–1} mol^{–1})$

asked Dec 11, 2018 by pady_1

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Consider the reaction : $Cl_2(aq) + H_2S(aq) \to S(s) + 2H^{+}(aq) + 2Cl^{–} (aq)$ The rate equation for this reaction is rate $= k [Cl_2] [H_2S]$ Which of these mechanisms is/are consistent with this rate equation ?
 (A) $Cl_2 + H_{2}S \to H^+ + Cl^- + Cl^+ + HS^- \;$ (slow)
$Cl^{+} + HS^{–} \to H^+ + Cl^- + S (fast)$
 $(B)\; H_2S \Leftrightarrow H^+ + HS^- $(fast equilibrium)
$Cl_2 + HS^{–} \to 2Cl^{–} +H^+ + S$ (slow)

asked Dec 11, 2018 by pady_1

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A solution containing $2.675\; g$ of $CoCl_3. 6 NH_3$ (molar mass =$ 267.5 \;g \;mol^{–1})$ is passed through a cation exchanger. The chloride ions obtained in solution were treated with excess of $AgNO_3$ to give $4.78\; g$ of $AgCl$ (molar mass $= 143.5\; g \;mol^{–1}$). The formula of the complex is (At. Mass of $Ag = 108 \;u$)

asked Dec 11, 2018 by pady_1

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The time for half life period of a certain reaction $A \to$ products is 1 hour. When the initial concentration of the reactant ‘A’, is $2.0\; mol\; L^{–1},$ how much time does it take for its concentration to come from $0.50\; to 0.25\; mol\; L^{–1}$ if it is a zero order reaction ?

asked Dec 11, 2018 by pady_1

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The standard enthalpy of formation of $NH_3$ is $–46.0\; kJ mol^{–1}.$ If the enthalpy of formation of $H_2$ from its atoms is $–436\; kJ mol^{–1}$ and that of $N_2$ is $–712\; kJ mol^{–1},$ the average bond enthalpy of $N–H$ bond in $NH_3$ is

asked Dec 11, 2018 by pady_1

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Infectious proteins are present in –

asked Jul 26, 2018 by pady_1

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An improved variety of transgenic basmati rice

asked Jul 26, 2018 by pady_1

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The part of Fallopian tube closest to the voary is

asked Jul 26, 2018 by pady_1

1 answer

Stirred-tank bioreactors have been designed for –

asked Jul 26, 2018 by pady_1

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Which one of the following not used in organic farming?

asked Jul 26, 2018 by pady_1

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dB is a standard abbreviation used of the quantitative expression of –

asked Jul 26, 2018 by pady_1

2 answers

Wind pollinated flowers are –

asked Jul 26, 2018 by pady_1

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Consider the following four statements (a–d) regarding kidney transplant and select the two correct ones out of these – (a) Even if a kidney transplant is proper the recipient may need to take immunosuppresants for a long time (b) The cell-mediated immune response is responsible for the graft rejection (c) The B-lymphocytes are responsible for rejection of the graft (d) The acceptance or rejection of a kidney transplant depends on specific interferons The two correct statements are –

asked Jul 26, 2018 by pady_1

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Which one of the following statements about human sperm is correct –

asked Jul 26, 2018 by pady_1

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Which one of the following does not follow the central dogma of molecular biology ?

asked Jul 26, 2018 by pady_1

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