Recent questions in JEEMAIN and NEET

Which one of the following reactions does not yield an alkyl halide ?

asked Dec 19, 2018 by pady_1

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Which one of the following reacts with concentrated sulphuric acid ?

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Mortar is a mixture of :

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A gas decolourises $Br_2$ in $CCl_4$ and forms a precipitate with ammonical silver nitrate. The gas is :

asked Dec 19, 2018 by pady_1

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The heat of combustion of $CH_4$, $C$(graphite) and $H_{2(g)}$ are respectively $20\;kcal$, $40\; kcal$ and $-10\; kcal$. The heat of formation of $CH_4$ is :

asked Dec 19, 2018 by pady_1

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Which of the following solutions cannot act as a buffer ?

asked Dec 19, 2018 by pady_1

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$75\%$ of first order reaction is completed in 32 minutes $50 \%$ of the reaction would have been completed in :

asked Dec 19, 2018 by pady_1

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4.5 moles each of hydrogen and iodin heated in a sealed 10 L vessel. At equilibrium 3 moles of HI were found. The equilibrium constant for $H_{2(g)} + I_{2(g)} \leftrightharpoons 2HI_{(g)} $ is :

asked Dec 19, 2018 by pady_1

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The cell reaction of a cell is $Mg_{(s)} + Cu^{2+}_{(aq)} \to Cu_{(s)} + Mg^{2+}_{(aq)}$ If the standard reduction potentials of magnesium and copper are $-0.33$ and $+2.38\; V$ respectively, the e.m.f of the cell is:

asked Dec 19, 2018 by pady_1

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The first emission line of hydrogen atomic spectrum in the Balmer series appears at (R = Rydberg constant) :

asked Dec 19, 2018 by pady_1

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An organic compound having carbon and hydrogen has $80\%$ carbon. The empirical formula of the hydrocarbon is :

asked Dec 19, 2018 by pady_1

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The effective atomic number of $Cr$ in $[Cr(NH_3)_6]Cl_3$ is :

asked Dec 19, 2018 by pady_1

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The conjugate base of $NH_2^-$ is :

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Hg sticks to the surface of the glass when it comes in contact with :

asked Dec 19, 2018 by pady_1

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$Be^{2+}$ is isoelectronic with :

asked Dec 19, 2018 by pady_1

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Reaction of benzene with alkyl halide in the presence of anhydrous $AlCl_3$ is called :

asked Dec 19, 2018 by pady_1

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Which one of the following can be used as an anaesthelic ?

asked Dec 19, 2018 by pady_1

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Silver chlorides dissolve in excess of $NH_4OH$. The cation present in this solution is :

asked Dec 19, 2018 by pady_1

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Liquid benzene burns in oxygen according to $2C_6H_{6(l)} + 15O_{2(g)} \to 12CO_{2(g)} + 6H_2O_{(g)}$ How much litres of oxygen are required for complete combustion of $39\;g$ of liquid $C_6H_6$ ?

asked Dec 19, 2018 by pady_1

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The pH of a solution is increased from 3 to 6. Its $H^+$ ion concentration will be :

asked Dec 19, 2018 by pady_1

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How much litres of $CO_2$ at STP will be formed when $100 \;mL$ of $M \; H_2SO_4$ reacts with excess of $Na_2CO_3$ ?

asked Dec 19, 2018 by pady_1

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As per the modern periodic law the physical and chemical properties of elements are periodic functions of their :

asked Dec 19, 2018 by pady_1

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One mole of argon gas will have least density at :

asked Dec 19, 2018 by pady_1

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Which of the following species has the highest ionization potential ?

asked Dec 19, 2018 by pady_1

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The radius of the nucleus is related to the mass number A by :

asked Dec 19, 2018 by pady_1

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Which one of the following set of the quantum numbers is not possible for a 4p electron ?

asked Dec 19, 2018 by pady_1

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The potential in the depletion layer is due to :

asked Dec 19, 2018 by pady_1

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A hole is :

asked Dec 19, 2018 by pady_1

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In the carbon cycle of fusion :

asked Dec 19, 2018 by pady_1

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Among electron, proton, neutron and $\alpha$-particle the maximum penetraion capacity is for :

asked Dec 19, 2018 by pady_1

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The number of $\alpha$ and $\beta$ particles, respectively, emitted in the radioactive decay $ _{90}X^{200} \to _{80}Y^{168}$ are :

asked Dec 19, 2018 by pady_1

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When $_{15}P^{30}$ decays to become $_{14}Si^{30}$ the particle released is :

asked Dec 19, 2018 by pady_1

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An electron remains undeflected when passing perpendicular to mutually perpendicular electric and magnetic fields. If the magnetic field is 8 Gauss and the electric field is $400\; V/m$, the velocity of the electron is :

asked Dec 19, 2018 by pady_1

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The radius of the Bohr orbit depends on $n$ as :

asked Dec 19, 2018 by pady_1

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The photoelectric work function of a metal surface is $2\;eV$. When light of frequency $1.5 \times 10^{15} Hz$ is incident on it, the maximum kinetic energy of the photo electrons, approximately is :

asked Dec 19, 2018 by pady_1

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A current carrying wire produces in the neighbourhood :

asked Dec 19, 2018 by pady_1

1 answer

A galvanometer has a resistance of $50 \; \Omega$ and a current of $0.01 \;A$ will cause full scale deflection. To convert this into an ammeter with full scale deflection for $5 \;A$, we have to connect approximately :

asked Dec 19, 2018 by pady_1

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If a long hollow copper pipe carries a current, the magnetic field produced will be :

asked Dec 19, 2018 by pady_1

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In a meter bridge the balancing length from the left end (standard resistance of one ohm is in the right gap) is found to be 20 cm. The value of the unknown resistance is :

asked Dec 19, 2018 by pady_1

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A wire of resistance $10 \Omega$ is elongated by $10 \%$, the resistance of the elongated wire :

asked Dec 19, 2018 by pady_1

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A parallel plate condenser with oil between the plates (dielectric constant of oil $K=2$) has a capacitance $C$. If the oil is removed, the capacitance of the capacitor becomes :

asked Dec 19, 2018 by pady_1

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The charges $+ 5 \; \mu C$ and $+ 10 \; \mu C$ are placed $20\; cm$ apart. The electric field at the mid point between the two charges is :

asked Dec 19, 2018 by pady_1

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Diamagnetic substance are :

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The null points are on the equatorial line of a bar magnet when the north pole of the magnet is pointing :

asked Dec 19, 2018 by pady_1

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Fraunhofer lines are due to :

asked Dec 19, 2018 by pady_1

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In the achromatic prism, we have :

asked Dec 19, 2018 by pady_1

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A compound microscope has an objective of focal length 4 mm and an eye piece of focal length 25 mm. The objective produces a real image at a distance of 180 mm. If the eye piece is in normal adjustment the magnification is :

asked Dec 19, 2018 by pady_1

1 answer

An object is placed 40 cm in front of a convex mirror of radius of curvature 20 cm. The image :

asked Dec 19, 2018 by pady_1

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A man stands in front of a hillock and fires a gun. He hears an echo after 1.5 s. The distance of the hillock from the man is (velocity of sound in air is 330 m/s) :

asked Dec 19, 2018 by pady_1

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A string in a musical instrument is 50 cm long and its fundamental frequency is 270 Hz. If the desired frequency of 1000 Hz is to be produced, the required string length is :

asked Dec 19, 2018 by pady_1

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