Recent questions tagged neet

If 'a' stands for the edge length of the cubic 3 systems : simple cubic, body centered cubic and face centered cubic, then the ratio of radii of the spheres in these systems will be respectively.

asked Jul 26, 2018 by pady_1

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Standard free energies of formation (in kJ/mol) at 298 K are -237.2, -394.4 and -8.2 for $H_2O(l)$, $CO_2 (g)$ and pentane(g) respectively The value of $E^o$ cell for the pentane-oxygen fuel cell is:

asked Jul 26, 2018 by pady_1

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A strong base can abstract an $\alpha$-hydrogen from:

asked Jul 26, 2018 by pady_1

1 answer

The rate constants $k_1$ and $k_2$ for two different reactions are $10^{16}.e^ {^\frac{-2000}{T}}$ and $10^{15}.e^{^\frac{-1000}{T}}$ respectively, the temperature at which $k_1$=$k_2$,, is:

asked Jul 26, 2018 by pady_1

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Number of moles of $MnO{_4}{^-}$ required to oxidize one mole of ferrous oxalate completely in acidic medium will be :

asked Jul 26, 2018 by pady_1

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With which one of the following elements silicon should be doped so as to give p-type of semiconductor?

asked Jul 26, 2018 by pady_1

2 answers

The correct order of increasing bond angles in the following triatomic species is :

asked Jul 26, 2018 by pady_1

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In a $S_N2$ substitution reaction of the type $R-Br+Cl^-\underrightarrow{DMF} R-Cl+Br^-$ Which one of the following has the highest relative rate ?

asked Jul 26, 2018 by pady_1

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Which of the following statements is not correct ?

asked Jul 26, 2018 by pady_1

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Green chemistry means such reactions which -

asked Jul 26, 2018 by pady_1

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The measurement of the electron position is associated with an uncertainty in momentum, which is equal to $1 \times 10^{ –18}$ g $cm s^{ –1}$. The uncertainty in electron velocity is : (Mass of an electron is $9 \times10^{–28}$ g)

asked Jul 26, 2018 by pady_1

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For the gas phase reaction, $PCl_5(g) \rightleftharpoons PCl_3(g) + Cl_2(g)$ Which of the following conditions are correct ?

asked Jul 26, 2018 by pady_1

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In a reaction of aniline a coloured product (C) was obtained. The structure of (C) would be -

asked Jul 26, 2018 by pady_1

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Which one of the following statements is not true ?

asked Jul 26, 2018 by pady_1

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How many moles of lead (II) chloride will be formed from a reaction between 6.5 g of PbO and 3.2 g of HCl ?

asked Jul 26, 2018 by pady_1

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Four diatomic species are listed below in different sequences. Which of these presents the correct order of their increasing bond order ?

asked Jul 26, 2018 by pady_1

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Which one of the following is most reactive towards electrophilic attack ?

asked Jul 26, 2018 by pady_1

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The correct order of decreasing second ionization enthalpy of Ti = 22, V = 23, Cr = 24 and Mn = 25 is -

asked Jul 26, 2018 by pady_1

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On the basis of the following Eº values, the strongest oxidizing agent is : $[Fe(CN)_6]^{4-}\rightarrow[Fe(CN)_6]^{3-}+e^{-1},E^o=-0.35v$ $Fe^{2+}\rightarrow Fe^{3+}+e^{-1},E^o=-0.77v$

asked Jul 26, 2018 by pady_1

1 answer

How many stereoisomers does this molecule have $CH_3CH = CHCH_2 CHBrCH_3$

asked Jul 26, 2018 by pady_1

1 answer

If uncertainty in position and momentum are equal, then uncertainty in velocity is -

asked Jul 26, 2018 by pady_1

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If the concentration of $OH^-$ ions in the reaction, $Fe(OH)_3(S)\rightleftharpoons Fe^{3+}(aq.)+3OH^-(aq)$ is decreased by $1\frac{1}{4}$ times, then equilibrium concentration of $Fe^{3+ }$will increase by -

asked Jul 26, 2018 by pady_1

1 answer

The bromination of acetone that occurs in acid solution is represented by this equation. $CH_3COCH_3(aq.)+Br_2(aq.)\longrightarrow CH_3COCH_2Br(aq)+H^+(aq)+Br^-(aq.)$ These kinetic data were obtained from given reaction concentrations. Initial rate, disappearance of $Br_2, Ms^{-1}$ $5.7 \times 10^{-5}$ $5.7 \times 10^{-5}$ $1.2 \times 10^{-4}$ $3.1 \times 10^{-4}$ Based on these data, the rate equation is :

asked Jul 26, 2018 by pady_1

1 answer

The dissociation equilibrium of a gas $AB_2$ can be represented as : $2AB_2 (g)\rightleftharpoons 2AB(g) + B_2 (g)$ The degree of dissociation is 'x' and is small s compared to 1. The expression relating the degree of dissociation (x) with equilibrium constant $K_p$ and total pressure P is -

asked Jul 26, 2018 by pady_1

0 answers

If a gas expands at constant temperature, it indicates that :

asked Jul 26, 2018 by pady_1

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Two thin lenses of focal lengths $f_1$ and $f_2$ are in contact and coaxial. The power of the combination is -

asked Jul 26, 2018 by pady_1

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A point performs simple harmonic oscillation of period T and the equation of motion is given by x = a sin ($(\omega t+\frac{\pi}{6})$). After the elapse of what fraction of the time period the velocity of the point will be equal to half of its maximum velocity ?

asked Jul 26, 2018 by pady_1

1 answer

The work function of a surface of a photosensitive material is 6.2 eV. The wavelength of the incident radiation for which the stopping potential is 5 V lies in the :

asked Jul 26, 2018 by pady_1

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Two radioactive materials $X_1$ and $X_2$ have decay constants $5\lambda$ and $\lambda$ respectively. If initially they have the same number of nuclei, then the ratio of the number of nuclei of $X_1$ to - that of $X_2$ will be $\frac{1}{e}$ after a time

asked Jul 26, 2018 by pady_1

1 answer

A current of 3 amp. flows through the $2\Omega$ resistor shown in the circuit. The power dissipated in the $5\Omega$ resistor is -

asked Jul 26, 2018 by pady_1

1 answer

Which two of the following five physical parameters have the same dimensions ? (a) Energy density (b) Refractive index (c) Dielectric constant (d) Young’s modulus (e) Magnetic field

asked Jul 26, 2018 by pady_1

1 answer

Curie temperature is the temperature above which -

asked Jul 26, 2018 by pady_1

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A wire of a certain material is stretched slowly by ten percent. Its new resistance and specific resistance become respectively -

asked Jul 26, 2018 by pady_1

1 answer

A closed loop PQRS carrying a current is placed in a uniform magnetic field. If the magnetic forces on segments PS, SR and RQ are $F_1$ ,$ F_2$ and $F_3$ respectively and are in the plane of the paper and along the directions shown, the force on the segment QP is :

asked Jul 26, 2018 by pady_1

1 answer

A boy is trying to start a fire by focusing Sunlight on a piece of paper using an equiconvex lens of focal length 10 cm. The diameter of the Sun is $1.39 \times 10^ 9$ m and its mean distance from the earth is $1.5 \times 10^{11}$ m. What is the diameter of the Sun’s image on the paper ?

asked Jul 26, 2018 by pady_1

1 answer

The wave described by y = 0.25 sin (10 $\pi X$ – 2$\pi f$), where x and y are in metres and t in seconds, is a wave travelling along the -

asked Jul 26, 2018 by pady_1

1 answer

On a new scale of temperature (which is linear) s and called the W scale, the freezing and boiling points of water are 39º W and 239º W respectively. What will be the temperature on the new scale, corresponding to a temperature of 39ºC on the Celsius scale ?

asked Jul 26, 2018 by pady_1

1 answer

In the circuit shown, the current through the 4$\Omega$ resistor is 1 amp when the points P and M are connected to a D.C. voltage source. The potential difference between the points M and N is

asked Jul 26, 2018 by pady_1

1 answer

If Q, E and W denote respectively the heat added, change in internal energy and the work done by a closed cycle process, then :

asked Jul 26, 2018 by pady_1

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Two periodic waves of intensities $I_1$ and $I_2$ pass through a region at the same time in the same direction. the sum of the maximum and minimum intensities is -

asked Jul 26, 2018 by pady_1

1 answer

A particle shows distance-time curve as given in this figure. The maximum instantaneous velocity of the particle is around the point :

asked Jul 26, 2018 by pady_1

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A particle moves in a straight line with a constant acceleration. It changes its velocity from 10 $ms^{–1}$ to 20 $ms^{–1}$ while passing through a distance 135 m in t second. The value of t is -

asked Jul 26, 2018 by pady_1

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If M (A, Z), $M_p$ and $M_n$ denote the masses of the nucleus $^{A}_ {Z} X$ , proton and neutron respectively in units of u (1u = 931.5 Me$\frac{V}{C}^2$ ) and BE represents its bonding energy in MeV, then -

asked Jul 26, 2018 by pady_1

1 answer

Two nuclei have their mass numbers in the ratio of 1 : 3. The ratio of their nuclear densities would be -

asked Jul 26, 2018 by pady_1

1 answer

A thin conducting ring of radius R is given a charge + Q. The electric field at the centre O of the ring due to the charge on the part AKB of the ring is E. The electric field at the centre due to the charge on the part ACDB of the ring is -

asked Jul 26, 2018 by pady_1

1 answer

Ascaris is characterized by :

asked Jul 26, 2018 by pady_1

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Consider the following statements about biomedical technologies, (i) During open heart surgery blood is circulated in the heart-lung machine (ii) Blockage in coronary arteries is removed by angiography (iii) Computerised Axial Tomography (CAT) shows detailed internal structure as seen in a section of body. (iv) X-ray provides clear and detailed images of organs like prostate glands and lungs Which two of the above statements are correct?

asked Jul 26, 2018 by pady_1

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Which one of the following in birds, indicates their reptilian ancestry?

asked Jul 26, 2018 by pady_1

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Main objective of production/use of herbicide resistant GM crops is to:

asked Jul 26, 2018 by pady_1

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Which one of the following is the correct statement regarding the particular psychotropic drug specified?

asked Jul 26, 2018 by pady_1

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