Previous Year Questions
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Which of the following factors may be regarded as the main cause of lanthanide contraction?
Hydrogen ion concentration in in a solution of will be
Consider an endothermic reaction, with the activation energies and for the backward and forward reactions, respectively. In general
Which one of the following statements is NOT true about the effect of an increase in temperature on the distribution of molecular speeds in a gas?
Which of the following compounds shows optical isomerism?
Of the following sets which one does NOT contain isoelectronic species?
Heating an aqueous solution of aluminium chloride to dryness will give
In both DNA and RNA, heterocyclic base and phosphate ester linkages are at-
The best reagent to convert pent-3-en-2-ol into pent -3-en-2-one is
If the bond dissociation energies of and (all diatomic molecules) are in the ratio of 1:1:0.5 and for the formation of is . The bond dissociation energy of will be
A schematic plot of versus inverse of temperature for a reaction is shown below
Which types of isomerism is shown by 2,3-dichlorobutane?
An ionic compound has a unit cell consisting of ions at the corners of a cube and ions on the centres of the faces of the cube. The empirical formula for this compound would be
An organic compound having molecular mass 60 is found to contain and while rest is oxygen. On heating it gives along with a solid residue. The solid residue give violet colour with alkaline copper sul
The solubility product of a salt having general formula , in water is: . The concentration of ions in the aqueous solution of the salt is
Which of the following oxides is amphoteric in character?
Electrolyte: Calculate Using appropriate molar conductance's of the electrolytes listed above at infinite dilution in at
Equimolar solutions in the same solvent have
Calomel on reaction with ammonium hydroxide gives
The photon of hard gamma radiation knocks a proton out of nucleus to form
Tertiary alkyl halides are practically inert to substitution by mechanism because of
For the reaction , at When and are compared at , it is found that
The oxidation state of chromium in the final product formed the reaction between and acidified potassium dichromate solution is :
The number of hydrogen atom(s) attached to phosphorus atom in hypophosphorous acid is
An amount of solid is placed in a flask already containing ammonia gas at a certain temperature and . Pressure. Ammonium hydrogen sulphide decomposes to yield and gases in the flask. When the decompos
In a multi-electron atom, which of the following orbitals described by the three quantum members will have the same energy in the absence of magnetic and electric fields?(A) (B) (C) (D) (E)
If we consider that , in place of , mass of carbon atom is taken to be the relative atomic mass unit, the mass of one mole of the substance will
Heating mixture of and will give
Lattice energy of an ionic compounds depends upon
In which of the following arrangements the order is NOT according to the property indicated against it?
The reactionis fastest when is
The correct order of the thermal stability of hydrogen halides is
-cresol reacts with chloroform in alkaline medium to give the compound which adds hydrogen cyanide to form, the compound . The latter on acidic hydrolysis gives chiral carboxylic acid. The structure o
Hydrogen bomb is based on the principle of
Acid catalyzed hydration of alkenes except ethene leads to the formation of
Alkyl halides react with dialkyl copper reagents to give
The value of the 'spin only' magnetic moment for one of the following configurations is . The correct one is
Two solutions of a substance (non electrolyte) are mixed in the following manner. of first solution of second solution. What is the molarity of the final mixture?
Elimination of bromine from 2-bromobutane results in the formation of-
What is the conjugate base of ?
Aluminium oxide may be electrolysed at to furnish aluminium metal (Atomic mass amu; 1 Faraday Coulombs). The cathode reaction is To prepare of aluminium metal by this method would require
The IUPAC name of the coordination compound is
Among the following acids which has the lowest value?
Which one of the following species is diamagnetic in nature?
can be taken as the time taken for the concentration of a reactant to drop to of its initial value. If the rate constant for a first order reaction is , the can be written as
The highest electrical conductivity of the following aqueous solutions is of
In silicon dioxide
Reaction of cyclohexanone with dimethylamine in the presence of catalytic amount of an acid forms a compound if water during the reaction is continuously removed. The compound formed is generally know
Due to the presence of an unpaired electron, free radicals are:
For a spontaneous reaction the , equilibrium constant and will be respectively
The decreasing order of nucleophilicity among the nucleophiles (A) (B) (C) (D) is
A reaction involving two different reactants can never be
Which one of the following methods is neither meant for the synthesis nor for separation of amines?
The lanthanide contraction is responsible for the fact that
Benzene and toluene form nearly ideal solutions. At , the vapour pressure of benzene is 75 torr and that of toluene is 22 torr. The partial vapour pressure of benzene at for a solution containing of b
Consider the reaction: carried out at constant temperature and pressure. If and are the enthalpy and internal energy changes for the reaction, which of the following expressions is true?
The oxidation state of in is
Pick out the isoelectronic structure from the following :(i) (ii) (iii) (iv)
The exothermic formation of is represented by the equation: Which of the following will increase the quantity of in an equilibrium mixture of and ?
The structure of diborane contains
Which one of the following cyano complexes would exhibit the lowest value of paramagnetic behaviour?(At. No. )
2 methylbutane on reacting with bromine in the presence of sunlight gives mainly
If is the degree of dissociation of , the Van't Hoff's factor (i) used for calculating the molecular mass is
Of the five isomeric hexanes, the isomer which can give two monochlorinated compounds is
Amongst the following the most basic compound is
Reaction of one molecule of with one molecule of 1,3 -butadiene at gives predominantly
The normal to the curve at any point is such that
If and then is a polynomial of degree
The plane cuts the sphere in a circle of radius
Let and be the distinct roots of , then is equal to
Area of the greatest rectangle that can be inscribed in the ellipse
If and , then lies on
Let , be a function defined by ,then is both one-one and onto when is the interval
If , then is equal to
The value of for which the sum of the squares of the roots of the equation assume the least value is
If the roots of the equation be two consecutive integers, then equals
If the plane passes through the midpoint of the line joining the centres of the spheres and then a equals
If the cube roots of unity are then the roots of the equation , are
If the equation , has a positive root , then the equation has a positive root, which is
If in a frequently distribution, the mean and median are 21 and 22 respectively, then its mode is approximately
If and are two non-zero complex numbers such that , then is equal to
If the angel between the line and the plane is such that then value of is
In a triangle . If and are the roots of then
If , then the solution of the equation is
If both the roots of the quadratic equation are less than 5 , then lies in the interval
The parabolas and divide the square region bounded by the lines and the coordinate axes. If are respectively the areas of these parts numbered from top to bottom ; then is
equals
A random variable has Poisson distribution with mean 2 . Then equals
A function is matched below against an interval where it is supposed to be increasing. Which of the following pairs is incorrectly matched?
The value of , is
The area enclosed between the curve and the coordinate axes is
Let be observations such that and . Then a possible value of among the following is
A spherical iron ball in radius is coated with a layer of ice of uniform thickness that melts at a rate of . When the thickness of ice is , then the rate at which the thickness of ice decreases is
is equal to
If and then
The differential equation representing the family of curves , where , is a parameter, is of order and degree as follows:
The distance between the line , and the plane is
Suppose is differentiable at and , then equals
The value of integral, is
Let and two events such that and , where stands for complement of event . Then events and are
If the letter of the word SACHIN are arranged in all possible ways and these words are written out as in dictionary, then the word SACHIN appears at serial number
A real valued function satisfies the functional equation where is given constant and is equal to
If , then the inverse of is
If is a real valued differentiable function satisfying and , then equals
Let be a non - negative continuous function such that the area bounded by the curve -axis and the ordinates and is . Then is
If the roots of the equation be two consecutive integers, then equals
The system of equations has infinite solutions, if is
The value of for which the sum of the squares of the roots of the equation assume the least value is
Three houses are available in a locality. Three persons apply for the houses. Each applies for one house without consulting others. The probability that all the three apply for the same house is
The angle between the lines and is
Let be differentiable for all . If and for , then
Let be a differentiable function having , . Then equals
If are in G.P., then the determinant is equal to
In a common base amplifier, the phase difference between the input signal voltage and output voltage is
A bullet fired into a fixed target loses half of its velocity after penetrating . How much further it will penetrate before coming to rest assuming that it faces constant resistance to motion?
Two voltmeters, one of copper and another of silver, are joined in parallel. When a total charge flows through the voltmeters, equal amount of metals are deposited. If the electrochemical equivalents
The intensity of gamma radiation from a given source is . On passing through of lead, it is reduced to . The thickness of lead which will reduce the intensity to will be
The function represents
When an unpolarized light of intensity is incident on a polarizing sheet, the intensity of the light which does not get transmitted is
A magnetic needle is kept in a non-uniform magnetic field. It experiences
An annular ring with inner and outer radii and is rolling without slipping with a uniform angular speed. The ratio of the forces experienced by the two particles situated on the inner and outer parts
A system goes from to via two processes and as shown in figure. If and are the changes in internal energies in the processes and respectively, then
A T shaped object with dimensions shown in the figure, is lying on a smooth floor. A force is applied at the point parallel to , such that the object has only the translational motion without rotation
The phase difference between the alternating current and is . Which of the following cannot be the constituent of the circuit?
One conducting tube can slide inside another as shown in figure, maintaining electrical contacts between the tubes. The magnetic field is perpendicular to the plane of the figure. If each tube moves t
Two point charges and are located at and respectively. The location of a point on the axis at which the net electric field due to these two point charges is zero is
The self inductance of the motor of an electric fan is . In order to impart maximum power at , it should be connected to a capacitance of
Two thin wire rings each having a radius are placed at a distance apart with their axes coinciding. The charges on the two rings are and . The potential difference between the centres of the two rings
A nuclear transformation is denoted by . Which of the following is the nucleus of element ?
A parallel plate capacitor is made by stacking equally spaced plates connected alternatively. If the capacitance between any two adjacent plates is then the resultant capacitance is
A particle of mass is kept on the surface of a uniform sphere of mass and radius . Find the work to be done against the gravitational force between them to take the particle far away from the sphere (
The electrical conductivity of a semiconductor increases when electromagnetic radiation of wavelength shorter than is incident on it. The band gap in for the semiconductor is
If are non coplanar vectors and is a real number then
A gaseous mixture consists of of helium and of oxygen. The ratio of the mixture is
A coil of inductance and resistance is connected to a source of voltage . The current reaches half of its steady state value in
A smooth block is released at rest on a incline and then slides a distance . The time taken to slide is times as much to slide on rough incline than on a smooth incline. The coefficient of friction is
A photocell is illuminated by a small bright source placed away. When the same source of light is placed away, the number of electrons emitted by photo-cathode would
A Young's double slit experiment uses a monochromatic source. The shape of the interference fringes formed on a screen is
The diagram shows the energy levels for an electron in a certain atom. Which transition shown represents the emission of a photon with the most energy?
If is stress and is young's modulus of material of a wire, the energy stored in the wire per unit volume is
A parachutist after bailing out falls without friction. When parachute opens, it decelerates at . He reaches the ground with a speed of . At what height, did he bail out?
Average density of the earth
A moving coil galvanometer has 150 equal divisions. Its current sensitivity is 10 - divisions per milliampere and voltage sensitivity is 2 divisions per millivolt. In order that each division reads 1
A fully charged capacitor has a capacitance . It is discharged through a small coil of resistance wire embedded in a thermally insulated block of specific heat capacity and mass . If the temperature o
A mass moves with a velocity and collides in-elastically with another identical mass. After collision the mass moves with velocity in a direction perpendicular to the initial direction of motion. Find
A spherical ball of mass is stationary at the top of a hill of height . It rolls down a smooth surface to the ground, then climbs up another hill of height and finally rolls down to a horizontal base
A long capillary tube is dipped in water. The water rises up to . If the entire arrangement is put in a freely falling elevator the length of water column in the capillary tube will be
The upper half of an inclined plane with inclination is perfectly smooth while the lower half is rough. A body starting from rest at the top will again come to rest at the bottom if the coefficient of
The relation between time and distance is where and are constants. The acceleration is
A particle is moving eastwards with a velocity of . In 10 seconds the velocity changes to northwards. The average acceleration in this time is
The block of mass moving on the frictionless horizontal surface collides with the spring of spring constant and compresses it by length . The maximum momentum of the block after collision is
An energy source will supply a constant current into the load if its internal resistance is
Two simple harmonic motions are represented by the equations and . The phase difference of the velocity of particle 1 with respect to the velocity of particle 2 is
The figure shows a system of two concentric spheres of radii and are kept at temperatures and , respectively. The radial rate of flow of heat in a substance between the two concentric spheres is propo
The change in the value of at a height above the surface of the earth is the same as at a depth below the surface of earth. When both and are much smaller than the radius of earth, then which one of t
Two thin, long, parallel wires, separated by a distance carry a current of in the same direction. They will
In a full wave rectifier circuit operating from mains frequency, the fundamental frequency in the ripple would be
A body of mass is accelerated uniformly from rest to a speed in a time . The instantaneous power delivered to the body as a function of time is given by
An observer moves towards a stationary source of sound, with a velocity one-fifth of the velocity of sound. What is the percentage increase in the apparent frequency?
In the circuit, the galvanometer shows zero deflection. If the batteries and have negligible internal resistance, the value of the resistor will be -
The bob of a simple pendulum is a spherical hollow ball filled with water. A plugged hole near the bottom of the oscillating bob gets suddenly unplugged. During observation, till water is coming out,
When two tuning forks (fork 1 and fork 2 ) are sounded simultaneously, 4 beats per second are heated. Now, some tape is attached on the prong of the fork 2 . When the tuning forks are sounded again, 6
A thin glass (refractive index ) lens has optical power of in air. Its optical power in a liquid medium with refractive index will be
If is the intensity of the principal maximum in the single slit diffraction pattern, then what will be its intensity when the slit width is doubled?
A circuit has a resistance of and an impedance of . The power factor of the circuit will be
If is the mid point of and is any point outside , then
If the kinetic energy of a free electron doubles, it's deBroglie wavelength changes by the factor
Let and . Then depends on
Two sources of equal are connected to an external resistance . The internal resistance of the two sources are and . If the potential difference across the source having internal resistance is zero, th
The moment of inertia of a uniform semicircular disc of mass and radius about a line perpendicular to the plane of the disc through the center is
A charged particle of mass and charge travels on a circular path of radius that is perpendicular to a magnetic field . The time taken by the particle to complete one revolution is
In a potentiometer experiment the balancing with a cell is at length . On shunting the cell with a resistance of , the balancing length becomes . The internal resistance of the cell is
Which of the following is incorrect regarding the first law of thermodynamics?
A heater coil is cut into two equal parts and only one part is now used in the heater. The heat generated will now be
A charged ball hangs from a silk thread , which makes angle with a large charged conducting sheet , as shown in the figure. The surface charge density of the sheet is proportional to
If a simple harmonic motion is represented by . its time period is
A car starting from rest accelerates at the rate through a distance , then continues at constant speed for time and then decelerates at the rate to come to rest. If the total distance traversed is , t
A block is kept on a frictionless inclined surface with angle of inclination . The incline is given an acceleration to keep the block stationary. Then is equal to
A fish looking up through the water sees the outside world contained in a circular horizon. If the refractive index of water is and the fish is 12 below the surface, the radius of this circle in is
Two point white dots are apart on a black paper. They are viewed by eye of pupil diameter . Approximately, what is the maximum distance at which these dots can be resolved by the eye? [ Take wavelengt
A uniform electric field and a uniform magnetic field are acting along the same direction in a certain region. If an electron is projected along the direction of the fields with a certain velocity the
Let and be distinct non- negative numbers. If the vectors and lie in a plane, then is
The resistance of hot tungsten filament is about 10 times the cold resistance. What will be resistance of and lamp when not in use ?
The temperature-entropy diagram of a reversible engine cycle is given in the figure. Its efficiency is
Consider a car moving on a straight road with a speed of . The distance at which car can be stopped is
Two concentric coils each of radius equal to are placed at right angles to each other. 3 ampere and 4 ampere are the currents flowing in each coil respectively . The magnetic induction in Weber at the
A particle of mass subjected to a force with . What will be its initial acceleration if it is released from a point away from the origin?
If radius of the nucleus is estimated to be fermi then the radius of nucleus is estimated to be nearly
For any vector , the value of is equal to
Starting with a sample of pure of it decays into in 15 minutes. The corresponding half life is
A body of mass while falling vertically downloads under gravity breaks into two-parts; a body of mass and a body of mass . The center of mass of bodies and taken together shifts compared to that of bo