Recent questions tagged jeemain

Which one of the following is not correct?

asked Sep 19, 2013 by meena.p

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How many corner's of $SiO_4$ unit are shared in the formation of three dimensional silicates?

asked Sep 19, 2013 by meena.p

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Diborane reacts with HCl in the presence of $AlCl_3$ and liberates:

asked Sep 19, 2013 by meena.p

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The $5^{th}$ term from the end in the expansion of $\bigg(\large\frac{x^3}{2}-\frac{2}{x}\bigg)^{12}$ is ?

asked Sep 19, 2013 by rvidyagovindarajan_1

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Solution "X" contains $Na_2 CO_3$ and $NaHCO_3.\;20 \;ml$ of $X$ when titrated using methyl orange indicator consumed $60\; ml $ of $0.1\;M\;HCl$ solution. In another experiment, $20 \;ml$ of X solution when titrated using phenolphthalein consumed $20\;ml$ of $0.1\;M\;HCl$ solution. The concentration (in mol $lit^{-1}$) of $Na_2CO_3$ and $NaHCO_3$ in X are respectively.

asked Sep 19, 2013 by meena.p

1 answer

The middle term in the expansion $(1+x)^{2n}$ is ?

asked Sep 19, 2013 by rvidyagovindarajan_1

1 answer

Observe the following statements:

asked Sep 19, 2013 by meena.p

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Match the following

asked Sep 19, 2013 by meena.p

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For which one of the following reactions,the entropy change is positive?

asked Sep 19, 2013 by meena.p

1 answer

The $pH$ of a buffer solution made by mixing $25\;ml$ of $\;0.02\;M\;NH_4OH$ and $25\;ml$ of $\;0.2\;M\;NH_4Cl$ at $25^{\circ}C$ is : $(pK_b\;of\;NH_4OH=4.8)$

asked Sep 19, 2013 by meena.p

1 answer

The degree of ionization of $\;0.10\;M$ lactic acid is $4.0 \%$

asked Sep 19, 2013 by meena.p

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Which one of the following plots is correct for a first reaction?

asked Sep 19, 2013 by meena.p

1 answer

The number of octahedral and tetrahedral holes respectively present in a hexagonal close packed (hcp) crystal of 'X' atoms are :

asked Sep 19, 2013 by meena.p

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The extent of charge of lead accumulator is determined by

asked Sep 19, 2013 by meena.p

1 answer

During the electrolysis of copper sulphate aqueous solution using copper electrode, the reaction taking place at the cathode is :

asked Sep 19, 2013 by meena.p

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The vapour pressure in mm of $Hg,$ of an aqueous solution obtained by adding 18 g of glucose $(C_6H_{12}O_6)$ to $180\;g$ of water at $100^{\circ}$ is :

asked Sep 18, 2013 by meena.p

1 answer

Which one of the following is an isotonic pair of solutions?

asked Sep 18, 2013 by meena.p

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At $T(k),$ the ratio of kinetic energies of $4\;g$ of $H_{2_{(g)}}$ and $8\;g$ of $O_{2_{g}}$ is :

asked Sep 18, 2013 by meena.p

1 answer

Which one of the following is an example of disproportionation reaction?

asked Sep 18, 2013 by meena.p

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Which one of the following statement is correct?

asked Sep 18, 2013 by meena.p

1 answer

Identify the correct set:

asked Sep 18, 2013 by meena.p

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The number of elements present in fourth period is :

asked Sep 18, 2013 by meena.p

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The basic of quantum mechanical model of an atom is :

asked Sep 18, 2013 by meena.p

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The number of radial nodes of $3s$ and $2p$ orbitals respectively are :

asked Sep 18, 2013 by meena.p

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Of the following, $NAND$ gate is

asked Sep 18, 2013 by meena.p

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The base current in a transistor circuit changes from $45\;\mu A$ to $140\;mu A$. Accordingly, the collector current changes from $0.2\;mA$ to $4.00\;mA$. The gain in current is

asked Sep 18, 2013 by meena.p

1 answer

A $U^{235}$ nuclear reactor generates energy at a rate of $3.70 \times 10^7\; J/s$ Each fission liberates $185\;MeV$ useful energy. If the reactor has to operate for $144 \times 10^4$ seconds, then the mass of the fuel needed is (Assume Avogadro's number $=6 \times 10^{23} \;mol^{-1},1 eV=1.6 \times 10^{-19}\;J)$

asked Sep 18, 2013 by meena.p

1 answer

The radius of $_{72}Te^{125}$ nucleus is $6$ fermi . The radius of $_{13}AI^{27}$ nucleus in meters is

asked Sep 18, 2013 by meena.p

1 answer

The work function of a metal is $2$ eV. If a radiation of wavelength 3000 A is incident on it, the maximum kinetic energy of the emitted photo electrons is

asked Sep 18, 2013 by meena.p

1 answer

Initially a photon of wavelength $\lambda _1$ falls on photocathode and emits an electron of maximum energy $E_1$. If the wave length of the incident photon i changed to $\lambda _2$, the maximum energy of the electron emitted becomes $E_2$. Then value of hc (h= Planck's constant , c= velocity of light) is

asked Sep 18, 2013 by meena.p

1 answer

The sensitivity of a galvanometer that measures current is decreased by $\large\frac{1}{40}$ times by using shunt resistance of $10 \;\Omega$. Then, the value of the resistance of the galvanometer is

asked Sep 18, 2013 by meena.p

1 answer

A series $LCR$ circuit is connected across a source of alternating emf of changing frequency and resonates at frequency $f_0$. Keeping capacitance constant, if the inductance (L) is increased by $\sqrt 3$ times and resistance is increased (R) by 1.4 times, the resonant frequency now is

asked Sep 18, 2013 by meena.p

1 answer

The ends of an element of zinc are kept at a small temperature difference $ \Delta T$ and a small current (I) is passed through the wire. Then, the heat developed per unit time

asked Sep 18, 2013 by meena.p

1 answer

In the meter bridge experiment, the length AB of the wire is 1 m. The resistors $X$ and $Y$ have values $5 \Omega$ and $2 \Omega$ respectively. When a shunt resistance $S$ is connected to $X$, the balancing point is found to be $0.625\;m$ from A. Then, the resistance of the shunt is

asked Sep 18, 2013 by meena.p

1 answer

In the circuit shown in the figure, the current $'I'$ is

asked Sep 18, 2013 by meena.p

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Two metal plates of area 'A' from a parallel plate capacitor with air in between the plates. The distance between the plate is 'd'. A metal plate of thickness $\large\frac{d}{2}$ and of the same area A is inserted between the plates to from two capacitors of capacitance $C_1$ and $C_2$ as shown in the figure. If the effective capacitance of the two capacitor is $C'$ and the capacitance of the capacitor initially is $C$, then $\large\frac{C'}{C}$ is

asked Sep 18, 2013 by meena.p

1 answer

A deflection magnetometer is adjusted and a magnet moment M is placed on it in the usual manner and the observed deflection is $\theta$. The period of oscillation of the needed before setting to the deflection is $T$. When the magnet is removed, the period of oscillation of needle is $T_0$ before settling to $0^{\circ}-0^{\circ}$. If the earth's induced magnetic field is $B_{H},$ the relation between $T$ and $T_0$ is

asked Sep 18, 2013 by meena.p

1 answer

Two short bar magnets have their magnetic moments $1.2\;Am^2$ and $1.0\;Am^2$. They are placed on a horizontal table parallel to each other at a distance of $20\;cm$ between their centers, such that their north poles pointing towards geographic south. They have common magnetic equatorial line. Horizontal component of earth's field is $3.6 \times 10^{-5}$ T. Then, the resultant horizontal magnetic induction at mid point of the line joining their centers is $\bigg(\large\frac{\mu _0}{4 \pi}$$=10 ^{-7} 11/m\bigg)$

asked Sep 18, 2013 by meena.p

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A short bar magnet having magnetic moment $4\;Am^2,$ placed in a vibrating magnetometer, vibrates with a time period of 8 seconds. Another short bar magnet having a magnetic moment $8\;Am^2$ vibrates with a time period of $6$ seconds. If the moment of inertia of the second magnet is $9 \times 10^{-2}\;kg\;m^2,$ the moment of inertia of the first magnet is (Assume that both magnets are kept in the same uniform magnetic induction field.)

asked Sep 18, 2013 by meena.p

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Fresnel diffraction is produced due to light rays falling on a small obstacle. The intensity of light at a point on a screen beyond an obstacle depends on

asked Sep 18, 2013 by meena.p

1 answer

A microscope consists of an objective of focal length $1.9\;cm$ and eye piece of focal length $5\; cm$. The two lenses are kept at a distance of $10.5 \;cm.$ If the image is to be formed at the least distance of distinct vision, the distance at which the object is to be placed before the objective is (Least distance of distinct vision is 25 cm)

asked Sep 18, 2013 by meena.p

1 answer

The two surfaces of a concave lens, made of glass of refractive index $1.5 $ have the same radii of curvature R. It is now immersed in a medium of refractive index $1.75$ then the lens,

asked Sep 17, 2013 by meena.p

1 answer

A source of sound of frequency 640 Hz is moving at a velocity of $\large\frac{100}{3}$$\;m/s$ along a road, and is at an instant 30 m away from a point A on the road (as shown in figure). A person standing at $O$, $40 \;m$ away from the road hears sound of apparent frequency $v^1$. The value of $v^1$ is (velocity of sound= 340 \;m/s)

asked Sep 17, 2013 by meena.p

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The term independent of $x$ in the expansion $(2x-\large\frac{1}{3x})^6$ is ?

asked Sep 17, 2013 by rvidyagovindarajan_1

1 answer

An air column in a tube $32\; cm$ long, closed at one end, is in resonance with a tuning fork. The air column in another tube, open at both ends, of length 66 cm is in resonance with another tuning fork. When these two tuning fork.The air column in another tube, open at both ends, of length 66 cm is in resonance with another tuning fork. When these two tuning forks are sounded together, they produce $8$ beats per seconds. Then the frequencies of the two tuning forks are , (Consider fundamental frequencies only)

asked Sep 17, 2013 by meena.p

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Two bodies $A$ and $B$ of equal surface area have thermal emissivities of $0.01$ and $0.81$ respectively. The two bodies are radiating energy at the same rate. Maximum energy is radiated from the two bodies A and B at wavelengths $\lambda _A$ and $\lambda_B$ respectively. Difference in these two wavelength is $1 \; \mu m $. If the temperature of the body A is $5802\;K,$ then value of $\lambda _B$ is

asked Sep 17, 2013 by meena.p

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If $x=\large\frac{1}{3}$, the greatest term in the expansion of $(1+4x)^8$ is ?

asked Sep 17, 2013 by rvidyagovindarajan_1

1 answer

Efficiency of a heat engine whose sink is at a temperature of 300 k is $40 \;\%$. To increase the efficiency to $60 \;\%$, Keeping the sink temperature constant, the source temperature must be increased by

asked Sep 17, 2013 by meena.p

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Three moles of an ideal monoatomic gas undergoes a cyclic process as shown in the figure. The temperature of the gas in different states marked as 1,2,3 and 4 are 400 K, 700 K, 2500 K and 1100 K respectively. The work done by the gas during the process $1 -2 -3 -4 -1$ is (Universal gas constant R)

asked Sep 17, 2013 by meena.p

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On a temperature scale Y, water freezes at $ -160^{\circ} \;Y$ and boils at $-50^{\circ}Y$. On this $Y$ scale, a temperature of $340\;K$ is:

asked Sep 17, 2013 by meena.p

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