The equation of state of a gas is given by where P, V, T are pressure, volume and temperature respectively, and a, b, c are constants. The dimensions of a and b are respectively
A capacitor of capacitance C0 is charged to a potential V0 and is connected with another capacitor of capacitance C as shown. After closing the switch S, the common potential across the two capacitors becomes V. The capacitance C is given by
Charge on isolated plates remains same
The r.m.s. speed of the molecules of a gas at 100°C is ν. The temperature at which the r.m.s. speed will be √3ν is
T (°C) = 846°C
As shown in the figure below, a charge +2C is situated at the origin O and another charge +5C is on the x-axis at the point A. The later charge from the point A is then brought to a point B on the y-axis. The work done is
A frictionless piston-cylinder based enclosure contains some amount of gas at a pressure of 400 kPa. Then heat is transferred to the gas at constant pressure in a quasi-static process. The piston moves up slowly through a height of 10cm. If the piston has a cross-section area of 0.3 m2, the work done by the gas in this process is
Wconst – Press = P × ΔV = 400 × 103 × 0.3 × 10 × 10–2 = 400 × 10 × 3 = 12000 = 12 kJ
An electric cell of e.m.f. E is connected across a copper wire of diameter d and length l. The drift velocity of electrons in the wire is vd. If the length of the wire is changed to 2l, the new drift velocity of electrons in the copper wire will be
A NOR gate and a NAND gate are connected as shown in the figure. Two different sets of inputs are given to this set up. In the first case, the input to the gates are A=0, B=0, C=0. In the second case, the inputs are A=1, B=0, C=1. The output D in the first case and second case respectively are
A bar magnet has a magnetic moment of 200 A.m2. The magnet is suspended in a magnetic field of 0.30 NA–1 m–1. The torque required to rotate the magnet from its equilibrium position through an angle of 30°, will be
Two soap bubbles of radii r and 2r are connected by a capillary tube-valve arrangement as shown in the diagram. The valve is now opened. Then which one of the following will result:
As pressure inside smaller bubble is greater than pressure inside bigger bubble . so air flows from smaller to bigger.
An ideal mono-atomic gas of given mass is heated at constant pressure. In this process, the fraction of supplied heat energy used for the increase of the internal energy of the gas is
The velocity of a car travelling on a straight road is 36 kmh–1 at an instant of time. Now travelling with uniform acceleration for 10 s, the velocity becomes exactly double. If the wheel radius of the car is 25 cm, then which of the following numbers is the closest to the number of revolutions that the wheel makes during this 10 s?
Two glass prisms P1 and P2 are to be combined together to produce dispersion without deviation. The angles of the prisms P1 and P2 are selected as 4° and 3° respectively. If the refractive index of prism P1 is 1.54, then that of P2 will be
δ1 + δ2 = 0 ⇒ (μ – 1)A1 = (μ2 – 1)A2 ⇒ μ2 = 1.72
The ionization energy of the hydrogen atom is 13.6 eV. The potential energy of the electron in n = 2 state of hydrogen atom is
Water is flowing in streamline motion through a horizontal tube. The pressure at a point in the tube is p where the velocity of flow is v. At another point, where the pressure is p/2, the velocity of flow is [density of water = ρ]
In the electrical circuit shown in figure, the current through the 4Ω resistor is
A wire of initial length L and radius r is stretched by a length l. Another wire of same material but with initial length 2L and radius 2r is stretched by a length 2l. The ratio of the stored elastic energy per unit volume in the first and second wire is,
A current of 1 A is flowing along positive x-axis through a straight wire of length 0.5 m placed in a region of a magnetic field given by B =(2ˆi+ 4ˆj) T. The magnitude and the direction of the force experienced by the wire respectively are
Two spheres of the same material, but of radii R and 3R are allowed to fall vertically downwards through a liquid of density σ. The ratio of their terminal velocities is
S1 and S2 are the two coherent point sources of light located in the xy-plane at points (0,0) and (0,3λ) respectively.Here λ is the wavelength of light. At which one of the following points (given as coordinates), the intensity of interference will be maximum?
An alpha particle (4He)has a mass of 4.00300 amu. A proton has mass of 1.00783 amu and a neutron has mass of 1.00867 amu respectively. The binding energy of alpha particle estimated from these data is the closest to
ΔM = 2(mp + mn) – mHe = 0.0300 amu E = ΔM C2 = 0.03 × 931 MeV ≈ 27.9 Mev
The equivalent resistance between the points a and b of the electrical network shown in the figure is
Four small objects each of mass m are fixed at the corners of a rectangular wire-frame of negligible mass and of sides a and b (a > b). If the wire frame is now rotated about an axis passing along the side of length b, then the moment of inertia of the system for this axis of rotation is
The de Broglie wavelength of an electron (mass = 1 × 10–30 kg, charge = 1.6 × 10-19 C) with a kinetic energy of 200 eV is (Planck’s constant = 6.6 × 10–34 J s)
An object placed at a distance of 16 cm from a convex lens produces an image of magnification m (m > 1). If the object is moved towards the lens by 8 cm then again an image of magnification m is obtained. The numerical value of the focal length of the lens is
m = f/f+u
As magnification can be same for two diffeent values of u only if they are of opposite sign.
The number of atoms of a radioactive substance of half-life T is N0 at t = 0. The time necessary to decay from N0/2 atoms to N0/10 atoms will be
N(t) = No x e-lt
A travelling acoustic wave of frequency 500 Hz is moving along the positive x-direction with a velocity of 300 ms–1. The phase difference between two points x1 and x2 is 60º. Then the minimum separation between the two pints is
A mass M at rest is broken into two pieces having masses m and (M-m). The two masses are then separated by a distance r. The gravitational force between them will be the maximum when the ratio of the masses [m:(M-m)] of the two parts is
A shell of mass 5M, acted upon by no external force and initially at rest, bursts into three fragments of masses M, 2M and 2M respectively. The first two fragments move in opposite directions with velocities of magnitudes 2V and V respectively. The third fragment will
By conservation of momentum
A bullet of mass m travelling with a speed v hits a block of mass M initially at rest and gets embedded in it. The combined system is free to move and there is no other force acting on the system. The heat generated in the process will be
A particle moves along X-axis and its displacement at any time is given by x(t) = 2t3 – 3t2 + 4t in SI units. The velocity of the particle when its acceleration is zero, is
x(t) = (2t3 – 3t2 + 4t)
A planet moves around the sun in an elliptical orbit with the sun at one of its foci. The physical quantity associated with the motion of the planet that remains constant with time is
Torque about the sun, S = 0 ⇒ Angular momentum is conserved
The fundamental frequency of a closed pipe is equal to the frequency of the second harmonic of an open pipe. The ratio of their lengths is
A particle of mass M and charge q is released from rest in a region of uniform electric field of magnitude E. After a time t, the distance travelled by the charge is S and the kinetic energy attained by the particle is T. Then, the ratio T/S
An alternating current in a circuit is given by I = 20 sin (100πt + 0.05π) A. The r.m.s. value and the frequency of current respectively are
I = 20sin (100 πt + 0.05π)
The specific heat c of a solid at low temperature shows temperature dependence according to the relation c = DT3 where D is a constant and T is the temperature in kelvin. A piece of this solid of mass m kg is taken and its temperature is raised from 20 K to 30 K. The amount of the heat required in the process in energy units is
Four identical plates each of area a are separated by a distance d. The connection is shown below. What is the capacitance between P and Q ?
The least distance of vision of a longsighted person is 60 cm. By using a spectacle lens, this distance is reduced to 12 cm. The power of the lens is
Here, v = – 60 cm, u = – 12 cm
A particle is acted upon by a constant power. Then, which of the following physical quantity remains constant ?
A particle of mass M and charge q, initially at rest, is accelerated by a uniform electric field E through a distance D and is then allowed to approach a fixed static charge Q of the same sign. The distance of the closest approach of the charge q will then be
In an n-p-n transistor
At two different places the angles of dip are respectively 30º and 45º. At these two places the ratio of horizontal component of earth’s magnetic field is
Note : Information is not sufficient in the given question. It can be solved only when magnetic field at these two places are equal.
Two vectors are given by A = iˆ + 2 ˆj + 2kˆ and B = 3iˆ + 6 ˆj + 2kˆ. Another vector C has the same magnitude as B but has the same direction as A . Then which of the following vectors represents C?
An equilateral triangle is made by uniform wires AB, BC, CA. A current I enters at A and leaves from the mid point of BC. If the lengths of each side of the triangle is L, the magnetic field B at the centroid O of the triangle is
A car moving at a velocity of 17 ms–1 towards an approaching bus that blows a horn at a frequency of 640 Hz on a straight track. The frequency of this horn appears to be 680 Hz to the car driver. If the velociy of sound in air is 340 ms–1, then velocity of the approaching bus is
A particle is moving with a uniform speed v in a circular path of radius r with the centre at O. When the particle moves from a point P to Q on the circle such that ∠POQ = θ, then the magnitude of the change in velocity is
Two simple harmonic motions are given by
x1 = a sin ωt + a cos ωt and
x2 = a sin ωt + a/√3 cos ωt
A small mass m attached to one end of a spring with a negligible mass and an unstretched length L, executes vertical oscillations with angular frequency ω0. When the mass is rotated with an angular speed ω by holding the other end of the spring at a fixed point, the mass moves uniformly in a circular path in a horizontal plane. Then the increase in length of the spring during this rotation is
A cylindrical block floats vertically in a liquid of density ρ1 kept in a container such that the fraction of volume of the cylinder inside the liquid is x1. then some amount of another immiscible liquid of density ρ2 (ρ2 < ρ1) is added to the liquid in the container so that the cylinder now floats just fully immersed in the liquids with x2 fraction of volume of the cylinder inside the liquid of density ρ1. The ratio ρ1/ρ2 will be
p1x1g = p1x2g + p2(1 – x2)g, as Bouyant force in both the cases are same
A sphere of radius R has a volume density of charge ρ = kr, where r is the distance from the centre of the sphere and k is constant. The magnitude of the electric field which exists at the surface of the sphere is given by (ε0 = permittivity of the free space)
By Gauss’s theorem
A particle of mass M and charge q is at rest at the midpoint between two other fixed similar charges each of magnitude Q placed a distance 2d apart. The system is collinear as shown in the figure. The particle is now displaced by a small amount x (x<< d) along the line joining the two charges and is left to itself. It will now oscillate about the mean position with a time period (ε0 = permittivity of free space)
Restoring force on displacement of x,
A body is projected from the ground with a velocity v = (3iˆ + 10 ˆj) ms –1 . The maximum height attained and the range of the body respectively are (given g = 10 ms–2)
V = 3i + 10j
Vx = 3
Vy = 10
The stopping potential for photoelectrons from a metal surface is V1 when monochromatic light of frequency v1 is incident on it. The stopping potential becomes V2 when monochromatic light of another frequency is incident on the same metal surface. If h be the Planck’s constant and e be the charge of an electron, then the frequency of light in the second case is
hν1 = φ0 + ev1 ——(1)
hν2 = φ0 + ev2 ——(2)
h (ν2 – ν1) = e (v2 – v1)
A cell of e.m.f. E is connected to a resistance R1 for time t and the amount of heat generated in it is H. If the resistance R1 is replaced by another resistance R2 and is connected to the cell for the same time t, the amount of heat generated in R2 is 4H. Then the internal resistance of the cell is
3 moles of a mono-atomic gas (γ = 5/3) is mixed with 1 mole of a diatomic gas (γ = 7/3). The value of γ for the mixture will be
Degree of freedom
i.e. f = 7/2
The magnetic field B = 2t2 + 4t2 (where t = time) is applied perpendicular to the plane of a circular wire of radius r and resistance R. If all the units are in SI the electric charge that flows through the circular wire during t = 0 s to t = 2 s is
Q. 56 – Q. 60 carry two marks each, for which one or more than one options may be correct. Marking of correct options will lead to a maximum mark of twoon pro rata basis. There willbe no negative marking for these questions. However, any marking of wrong option will lead to award of zero mark against the respective question – irrespective of the number of corredt options marked.
Q. If E and B are the magnitudes of electric and magnetic fields respectively in some region of space, then the possibilities for which a charged particle may move in that space with a uniform velocity of magnitude v are
An electron of charge e and mass m is moving in circular path of radius r with a uniform angular speed ω. Then which of the following statements are correct ?
Magnetic moment μ = IA
Angular momentum = 2 m dA/dt
A biconvex lens of focal length f and radii of curvature of both the surfaces R is made of a material of refractive index n1. This lens is placed in a liquid of refractive index n2. Now this lens will behave like
A block of mass m (= 0.1 kg) is hanging over a frictionless light fixed pulley by an inextensible string of negligible mass. The other end of the string is pulled by a constant force F in the verticaly downward direction. The linear momentum of the block increase by 2 kg ms–1 in 1 s after the block starts from rest. Then, (given g = 10 ms–2)
F – mg = 2
F = 2 + mg = 3 N
.
∴ W by tension = F × 10 = 3 × 10 = 30 J
W against gravity = mg × s = = 1 × 10 = 10 J
A bar of length l carrying a small mass m at one of its ends rotates with a uniform angular speed ω in a vertical plane about the mid-point of the bar. During the rotation, at some instant of time when the bar is horizontal, the mass is detached from the bar but the bar continues to rotate with same ω. The mass moves vertically up, comes back and reches the bar at the same point. At that place, the acceleration due to gravity is g.
In diborane, the number of electrons that account for bonding in the bridges is
Each bridging bond is formed by two electrons. Hence four electrons account for bonding in the bridges.
The optically active molecule is
Others are meso compound due to presence of plane of symmetry.
A van der Waals gas may behave ideally when
A van der waals gas may behave ideally when pressure is very low as compressibility factor (Z) approaches 1. At high temperature Z > 1.
The half-life for decay of 14C by β-emission is 5730 years. The fraction of 14C decays, in a sample that is 22,920 years old, would be
2-Methylpropane on monochlorination under photochemical condition give
Ratio of A: B is 5:9
For a chemical reaction at 27°C, the activation energy is 600 R. The ratio of the rate constants at 327°C to that of at 27°C will be
Chlorine gas reacts with red hot calcium oxide to give
2CaO + 2Cl2 → CaCl2+O2 ↑ Red hot
Correct pair of compounds which gives blue colouration/precipitate and white precipitate, respectively, when their Lassaigne’s test is separately done is
Organic compound
The change of entropy (dS) is defined as
In O2 and H2O2, the O–O bond lengths are 1.21 and 1.48 Å respectively. In ozone, the average O–O bond length is
Bond length is nearly average of bond length of O – O in
The IUPAC name of the compound X is
2, 2-Dimethyl-4-oxopentanenitrile
At 25°C, the solubility product of a salt of MX2 type is 3.2 × 10–8 in water. The solubility (in moles/lit) of MX2 in water at the same temperature will be
2× 10–3
In SOCl2, the Cl–S–Cl and Cl–S–O bond angles are
(+)-2-chloro-2-phenylethane in toluene racemises slowly in the presence of small amount of SbCl5, due to the formation of
SbCl5 removes Cl– from the substrate to generate a planar carbocation, which is then subsequently attacked by Cl– from both top and bottom to result in a racemic mixture.
Acid catalysed hydrolysis of ethyl acetate follows a pseudo-first order kinetics with respect to ester. If the reaction is carried out with large excess of ester, the order with respect to ester will be
With large excess of ester the rate of reaction is independent of ester concentration.
The different colours of litmus in acidic, neutral and basic solutions are, respectively
Baeyer’s reagent is
The correct order of equivalent conductances at infinite dilution in water at room temperature for H+, K+, CH3COO– and HO– ions is
Nitric acid can be obtained from ammonia via the formations of the intermediate compounds
In the following species, the one which is likely to be the intermediate during benzoin condensation of benzaldehyde, is
The correct order of acid strength of the following substituted phenols in water at 28°C is
As order of electron withdrawing nature from benzene ring : –NO2>–Cl>–F
For isothermal expansion of an ideal gas, the correct combination of the thermodynamic parameters will be
For isothermal process, ΔT=0
∴ ΔU= nCvΔT=0
ΔH = nCpΔT= 0
From first law of thermodynamics
ΔU= Q +W
As ΔU = 0
∴ Q= W ≠ 0
Addition of excess potassium iodide solution to a solution of mercuric chloride gives the halide complex
HgCl2 + 4KI → K2[HgI4] + 2KCl
Amongst the following, the one which can exist in free state as a stable compound is
n = no. of atoms of a particular type
v = valency of the atom
Molecules with fractional degree of unsaturation cannot exist with stability
A conducitivity cell has been calibrated with a 0.01 M 1:1 electrolyte solution (specific conductance, k=1.25 x 10–3 S cm-1) in the cell and the measured resistance was 800 ohms at 25°C. The constant will be
The orange solid on heating gives a colourless gas and a greensolid which can be reduced to metal by aluminium powder. The orange and the green solids are, respectively
The best method for the preparationof 2,2 -dimethylbutane is via the reaction of
Corey-House alkane synthesis gives the alkane in best yield
The condition of spontaneity of process is
dGP,T = –ve is the criterion for spontaneity
The increasing order of O-N-O bond angle in the species NO2+ , NO2and NO2– is
No option is correct correct ans : NO2+ > NO2 > NO2–
The correct structure of the dipeptide gly-ala is
Equivalent conductivity at infinite dilution for sodium-potassium oxalate ((COO–)2Na+K+) will be [given, molar conductivities of oxalate, K+ and Na+ ions at infinite dilution are 148.2, 50.1, 73.5 S cm2mol–1, respectively]
For BCl3, AlCl3 and GaCl3 the increasing order of ionic character is
Ionic character is inversely proportional to polarising power of cation.
BCl3<GaCl3<AlCl3
At 25°C, pH of a 10–8 M aqueous KOH solution will be
The reaction of nitroprusside anion with sulphide ion gives purple colouration due to the formation of
⇒ Tetra anionic complex of iron (II) co-ordinating to one NOS– ion
An optically active compound having molecular formula C8H16 on ozonolysis gives acetone as one of the products. The structure of the compound is
Mixing of two different ideal gases under istohermal reversible condition will lead to
The ground state electronic configuration of CO molecule is
When aniline is nitrated with nitrating mixturte in ice cold condition, the major product obtained is
The measured freezing point depression for a 0.1 m aqueous CH3COOH solution is 0.19°C. The acid dissociation constant Ka at this concentration will be (Given Kf, the molal cryoscopic constant = 1.86 K kg mol–1)
ΔTf = i × kf × m
The ore chromite is
Chromite ore is FeCr2O4
‘Sulphan’ is
Sulphan is pure liquid SO3
Pressure-volume (PV) work done by an ideal gaseous system at constant volume is (where E is internal energy of the system)
From 1st law of thermodynamic
ΔE = q+w.
Now w = PΔV. for Δv = 0 w = 0
Amongst [NiCl4]2–, [Ni(H2O)6]2+,[Ni(PPh3)2Cl2], [Ni(CO)4] and [Ni(CN)4]2–, the paramagnetic species are
Number of hydrogen ions present in 10 millionth part of 1.33 cm3 of pure water at 25°C is
Ribose and 2-deoxyribose can be differentiated by
In deoxyribose, one –OH group is missing, which will prevent the formation of osazone.
The standard Gibbs free energy change (ΔG0) at 25°C for the dissociation of N2O4(g) to NO2(g) is (given, equilibrium constant = 0.15, R=8.314 JK/mol)
ΔG0 = – RTlnk
Bromination of PhCOMe in acetic acid medium produces mainly
Silicone oil is obtained from the hydrolysis and polymerisation of
Reaction proceeds via benzyne mechanism with intermediate as
Identify the CORRECT statement
In borax the number of B–O–B links and B–OH bonds present are, respectively,
Reaction of benzene with Me3COCl in the presence of anhydrous AlCl3 gives
It is because of rearrangement during which initially formed acyl cation loses CO to form stable tertiary butyl cation
1 × 10–3 mole of HCl is added to a buffer solution made up of 0.01 M acetic and 0.01 M sodium acetate. The final pH of the buffer will be (given, pKa of acetic acid is 4.75 at 25°C)
The best method for preparation of Me3CCN is
It’s a SN2 reaction where Me3C–MgBr + Cl – CN → Me3C – CN + Mg (Cl)Br
On heating, chloric acid decompose to
Q. 116 – Q. 120 carry two marks each, for which one or more than one options may be correct. Marking of correct options will lead to a maximum mark of two on pro rata basis. There will be no negative marking for these questions. However, any marking of wrong option will lead to award of zero mark against the respective question-irrespective of the number of correct options marked.
Q. Consider the following reaction for 2NO2(g) + F2(g) → 2NO2F(g). The expression for the rate of reaction interms of the rate of change of partial pressures of reactant and product is/are
Tautomerism is exhibited by
Availability of acidic H-atoms at these positions(shown by arrow marks) enable the compounds to show keto-enol tautomerism
The important advantage(s) of Lintz and Donawitz (L.D.) process for the manufacture of steel is (are)
In basic medium the amount of Ni2+ in a solution can be estimated with the dimethylglyoxime reagent. The correct statement(s) about the reaction and the product is(are)
Correct statement(s) in cases of n-butanol and t-butanol is (are)
More branching means less boiling point and high solubility
A point P lies on the circle x2 + y2 = 169. If Q = (5,12) and R = (–12,5), then the angle ∠QPR is
Q (5,12) R (–12,5) 0 (0,0)
mOQ . mOR = –1, so ∠QOR = π/2 Hence ∠QPR = π/4
A circle passing through (0,0), (2,6), (6,2) cuts the x-axis at the point P ≠ (0,0). Then the length of OP, where O is origin, is
Circle passes through (0,0)
so, x2+y2+2gx+2fy = 0
(2,6) & (6,2) lies on it so,
22+62+4g+12f = 0 — (1)
22+62+12g+4f = 0 — (2)
⇒ From (1) & (2), g = f = –5/2
Eqn. of circle is x2+y2–5x–5y=0
For y = 0, x(x–5)=0 ⇒ x=0, x=5
OP = 5
The locus of the midpoints of the chords of an ellpse x2+4y2 = 4 that are drawn form the positive end of the minor axis, is
Positive end of minor axis (0,1) but mid-pt be (h,k) x=2h, y=2k–1 lies on ellipse
Here on ellipse of centre (0,1/2), major axis 2, minor axis 1
A point moves so that the sum of squares of its distances from the points (1,2) and (–2,1) is always 6. Then its locus is
Let (h,k) be co-ordinates of the point
(h–1)2 + (k–2)2 + (h+2)2 + (k–1)2=
6 ⇒ h2+k2+h – 3k + 2 = 0
a circle with centre (-1/2,3/2) and radius 1/√2
For the variable t, the locus of the points of intersection of lines x–2y = t and x+2y = 1/t is
(x–2y) (x+2y) = 1 ⇒ x2 - 4y2 = 1
The number of solutions of the equation x+y+z = 10 in positive integers x,y,z is equal to
10–1 C3–1 = 9C2 = 36
For 0 ≤ P,Q ≤ π/2 , if sin P + cos Q=2, then the value of tan(P+Q/2) is
P = π/2 , Q = 0
If α and β are the roots of x2 – x+1 = 0, then the value of α2013 + β2013 is equal to
α = – ω, – ω2
– ω2013 – ω2x2013 = – (ω3)671 – (ω3)2x671 = – 2
Let
f(x) = 2100 x+1,
g(x) = 3100 x+1.
Then the set of real numbers x such that f(g(x)) = x is
f(x) = 2100x+1 ; g(x) = 3100 x+1
The limit of x sin(e1/x) as x → 0
–1≤ sine1/x≤1, -x≤ xsin(e1/x) ≤x
Then the matrix P3 + 2P2 is equal to
|P −λI = 0 , characteristics equation of P is P3+2P2–P–2I = 0
P3+2P2=P+2I
If α, β are the roots of the quadratic equation x2+ax+b=0, (b≠0); then the quadratic equation whose roots are α - 1/β, β - 1/α
α+β = –a, αβ = b
The value of is equal to
= 999
(1+a2+b2)3
= C1 → C1 – bC3, C2 → aC3 + C2
If the distance between the foci of an ellipse is equal to the length of the latus rectum, then its eccentricity is
2ae = 2b2/a
e = b2/a2 = 1-e2
e2 + e–1 = 0
= e = 1/2 (√5-1)
For the curve x2+4xy+8y2=64 the tangents are parallel to the x-axis only at the points
x2+4xy+8y2 = 64
⇒ 2x+4xy′+4y+16yy′=0
⇒ (4x+16y)y′ = – (2x+4y)
2x + 4y = 0
The value of
Let f(θ) = (1+sin2θ)(2–sin2θ). Then for all values of θ
f(θ) = (1+sin2θ) (2–sin2θ)
f(θ)=(1+sin2θ)(1+cos2θ)
=2+sin2θcos2θ
= 2 + 1/2sin2θ
2≤ f(θ)≤ 9/4
Then
so L.H.D at x = 2 is 9, R.H.D at x = 2 is –3
so f(x) is continuous but not differentiable at x = 2
If f(x) = ex (x – 2)2 then
f′(x) = ex [(x –2)2 + 2(x – 2)]
= ex [x2 – 2x] = ex.x(x – 2)
sign scheme of f′(x) will be
so f is increasing in (–∞, 0) and (2, ∞) and decreasing in (0, 2)
Let f : R → R be such that f is injective and f(x)f(y) = f(x +y) for all x, y ∈ R. If f(x), f(y), f(z) are in G.P., then x, y, z are in
f (x + y) = f(x).f(y), so f(x) = akx
akx, aky, akz are in G.P
a2ky = ak(x + z) ⇒ 2y
= x + z, so x, y, z are in A.P
The number of solutions of the equation
(x + 1) = 3, x = 2 so only one solution
The area of the region bounded by the parabola y = x2 –4x + 5 and the straight line y = x + 1 is
The value of the integral
Then
f(x) = sinx + 2cos2x
= – 2sin2x + sinx + 2
= – 2 (sin2x – ½ sinx) + 2
f(x) will be minimum when (sinx-1/4)2 is maximum at x = π/2
Each of a and b can take values 1 or 2 with equal probability. The probability that the equation ax2 + bx + 1 = 0 has real roots, is equal to
ax2 +bx + 1 = 0 has real roots for b2 –4a ≥ 0
So a has to be 1 and b has to be 2
so probability is = 1/2 x 1/2 = 1/4
There are two coins, one unbiased with probability 1/2 of getting heads and the other one is biased with probability 3/4 of getting heads. A coin is selected at random and tossed. It shows heads up. Then the probability that the unbiased coin was selected is
H → Event of head showing up
B → Event of biased coin chosen
UB → Event of unbiased coin chosen
For the variable t, the locus of the point of intersection of the lines 3tx – 2y + 6t =0 and 3x + 2ty – 6 = 0 is
The point of intersection of 3tx – 2y + 6t = 0 and 3x + 2ty – 6 = 0 is
Considering t = tan θ, x = 2cos 2θ, y = 3.sin 2θ
so locus of point of intersection is
Cards are drawn one-by-one without replacement from a well shuffled pack of 52 cards. Then the probability that a face card (Jack, Queen or King) will appear for the first time on the third turn is equal to
P (face card on third turn) = P (no face card in first turn) × P (no face card in 2nd turn) × P (face card in 3rd turn)
Lines x + y = 1 and 3y = x + 3 intersect the ellipse x2 + 9y2 = 9 at the points P,Q,R. The are of the triangle PQR is
The number of onto functions from the set {1, 2, ..........., 11} to set {1, 2, .... 10} is
Let z1 = 2 + 3i and z2 = 3 + 4i be two points on the complex plane. Then the set of complex numbers z satisfying |z – z1|2 + |z – z2|2 = |z1 – z2|2 represents
Clearly the locus of Z is a circle with Z1 & Z2 as end point of diameter.
Let p(x) be a quadratic polynomial with constant term 1. Suppose p(x) when divided by x – 1 leaves remainder 2 and when divided by x + 1 leaves remainder 4. Then the sum of the roots of p(x) = 0 is
P(x) = ax2 + bx + 1
P(1) = a + b + 1 =
2P(–1) = a – b + 1 =
4 so b = –1, a = 2
sum of roots of P(x) is -b/a = 1/2
Eleven apples are distributed among a girl and a boy. Then which one of the following statements is true ?
Five numbers are in H.P. The middle term is 1 and the ratio of the second and the fourth terms is 2:1. Then the sum of the first three terms is
Let a, b, 1, c, d are H.P
so, sum of the first three terms 3 + 3/2 + 1 = 11/2
R.H.L. ≠ L.H.L
The maximum and minimum values of cos6θ + sin6θ are respectively
sin6θ + cos6θ = 1 – 3sin2θ.cos2θ
1-3/4sin2θ
If a, b, c are in A.P., then the straight line ax + 2by + c = 0 will always pass through a fixed point whose co-ordinates are
a(x + y) + c( y + 1) = 0
x = 1, y = – 1
If one end of a diameter of the circle 3x2 + 3y2 – 9x + 6y + 5 = 0 is (1, 2) then the other end is
Center (3/2,-1)
Let the other point be (h, k)
The value of cos2750 + cos2450 + cos2150 – cos2300 – cos2600 is
cos15º= sin75º
cos275º + cos245º + cos215º – cos230º – cos260º
= cos275º + sin275º + cos2 45º – cos230º – cos260º
= 1 +1/2-3/4-1/4
= 1/2
Suppose z= x + iy where x and y are real numbers and i = √-1, The points (x,y) for which z-1/z+1 is real,lie on
The equation 2x2 + 5xy – 12y2 = 0 represents a
2x2 + 5xy – 12y2 = 0
(x + 4y) (2x – 3y) = 0
The line y = x intersects the hyperbola x2/9 - y2/25 = 1,at the points P and Q. The eccentricity of ellipse with PQ as major axis and minor axis of length 5/√2 is
The equation of the circle passing through the point (1, 1) and the points of intersection of x2 + y2 – 6x – 8 = 0 and x2 + y2 – 6 = 0 is
Six positive numbers are in G.P., such that their product is 1000. If the fourth term is 1, then the last term is
In the set of all 3×3 real matrices a relation is defined as follows. A matrix A is related to a matrix B if and only if there is a non-singular 3×3 matrix P such that B = P–1AP. This relation is
R = {(A, B) | B = P–1 AP}
A = I–1AI ⇒ (A, A) ∈ R ⇒ R is reflexive
Let (A, B) ∈ R , B = P–1AP PB = AP
⇒ PBP–1 = A ⇒ A = (P–1)–1 B(P–1)
⇒ (B, A) ∈R, ⇒ R is symmetric
Let (A, B) ∈ R, (B, C) ∈ R
A = P–1BP and B = Q–1CQ
A = P–1Q–1C QP = (QP)–1 C(QP)
⇒ (A, C) ∈R
The number of lines which pass through the point (2, –3) and are at the distance 8 from the point (–1, 2) is
The maximum distance of the line passing through (2, –3) from (–1, 2) is √34 . So there is no possible line
If α, β are the roots of the quadratic equation ax2 + bx + c = 0 and 3b2 = 16ac then
3b2 = 16ac
For any two real numbers a and b, we define a R b if and only if sin2 a + cos2b = 1. The relation R is
sin2a + cos2b = 1
Reflexive : sin2a + cos2a = 1
⇒ aRa
sin2a + cos2b = 1,
1 – cos2a + 1 – sin2b
= 1
sin2b + cos2a = 1
⇒ bRa
Hence symmetric Let aRb, bRc
sin2a + cos2b = 1 ............. (1)
sin2b + cos2c = 1 ............... (2)
(1) + (2)
sin2a + cos2c = 1
Hence transitive therefore equivalence relation.
Let n be a positive even integer. The ratio of the largest coefficient and the 2nd largest coefficient in the expansion of (1 + x)n is 11:10. The the number of terms in the expansion of (1 + x)n is
Let n = 2m
Let exp(x) denote exponential function ex. If f(x) = exp(x1/x), x > 0 then the minimum value of f in the interval [2, 5] is
f( x ) = ex1/x
g(x) = log f(x) = x1/x
g(x) increases is (0, e) & decreases in (e, ∞) it will be minimum at either 2 or 5
21/2 > 51/5 ⇒ minimum value of f(x) = exp(51/5)
The sum of the series
On integrate (1 + x)25 twice 1st under the limit 0 to x & then 0 to 1 we get sum =
Five numbers are in A.P. with common difference ≠ 0. If the 1st, 3rd and 4th terms are in G.P., then
Let a, a + d, a + 2d, a + 3d, a + 4d are five number in A.P.
The minimum value of the function f(x) = 2|x – 1| + |x – 2| is
f(x) will be minimum at x = 1
If P, Q, R are angles of an isosceles triangle and P, ∠= π/2 then the value of (cosP/3 - isinP/3)3 + (cosQ + isinQ) (cosR – isinR) + (cosP – isinP) (cosQ – isinQ) (cosR – isinR) is equal to
(cosP/3 - isinP/3)3 + (cosQ + isinQ) (cosR – isinR) + (cosP – isinP) (cosQ – isinQ) (cosR – isinR) =
A line passing through the point of intersection of x + y = 4 and x – y = 2 makes an angle tan–1(3/4) with the x-axis. It intersects the parabola y2 = 4(x–3) at points (x1, y1) and (x2, y2) respectively. Then |x1–x2| is equal to
Let [a] denote the greatest integer which is less than or equal to a. Then the value of the integral
If sin2 θ+ 3 cos θ = 2 , then cos3 θ+ sec3 θ is
Cos2θ− 3Cosθ + 1 = 0
cosθ + 1/cosθ = 3
Then the value of logey is
The value of the infinite series
The value of the integral