When the plane of the armature of an A.C. generator is parallel to the field in which it is rotating, then
In the Bohr's hydrogen atom model, the radius of the stationary orbit is directly propotional to n
In photoelectric effect if the intensity of light is doubled then maximum kinetic energy of photoelectrons will become
The resistance of a wire of uniform diameter d and lengths L is R. The resistance of another wire of the same material but diameter 2d and length 4L will be
A ball is allowed to fall from a height of 10 m. If there is 40% loss of energy due to impact, then after one impact ball will go up to
A particle of mass m is executing uniform circular motion on a path of radius r. If p is the magnitude of its linear momentum. The radial force acting on the particle is
When a certain weight is suspended from a long uniform wire, its length increases by one cm. If the same material and length but having a diameter half of the first one then the increase in length will be
A capacitor of capacity C has reactance X. If capacitance and frequency become double, then reactance will be
The main function of coupling capacitor in and RC coupled common either amplifier is to:
Three capacitors each of capacity 4 μF are to be connected in such a way that their effective capacitance is 6 μF. This can be done by connecting
The molar specific heat at constant pressure for a monoatomic gas is
Temperature of water at the surface of lake is 20ºC. Then temperature of water just below the lower surface of ice layer is
A van is moving with a speed of 72 kmph on a level road, where the coefficient of friction between its tyres and road is 0.5. The minimum radius of curvature, the road must have for safe driving of van is (g = 10ms−2 )
The escape velocity on the earth is 11.2 kms−1 . The escape velocity on a planet of mass M/4 and radius R/2 is (M and R are the mass of earth and its radius)
A 5000 kg rocket is set for vertical firing. The exhaust speed is 800 m/s. To give an initial upward acceleration of 20 m/s2, amount of gas ejected per second to supply needed thrust will be (g=10 m/s2)
The electric current in a circular coil of two turns produced a magnetic induction of 0.2T at its centre. The coil is unwound and is rewound into a circular coil of four turns. The magnetic induction at the centre of the coil now is, in tesla (if same current flows in the coil)
Two similar bar magnets of the same mass and dimensions freely suspended by threads in a horizontal plane are found to make 12 oscillations and 15 oscillations per minute. Then their magnetic moments are in the ratio of
If the radius of a soap bubble is four times that of another, then the ratio of their pressures will be
A body is moved along a straight line by a machine delivering constant power. The distance moved by the body in time t sec is proportional
A bullet is fired from a gun with a velocity of 1000 m−s⁻1 in order to hit a target 100 m away. At what height above the target should the gun be aimed? (Resistance of air is negligible and g = 10 m−s⁻1)
A palyer caught a cricket ball of mass 150 gm moving at a rate of 20 m/s. If the catching process be completed in 0.1 s, then the force of the blow exerted by the ball on the hands of the player is
If a simple pendulum oscillates with an amplitude of 50 mm and time period of 2 s, then its maximum velocity is
A satellite is in elliptical orbit about the earth (radius = 6400 km). At perigee it has an altitude of 1100 km and at the apogee its altitude is 4100 km. The major axis of the orbit is
An aeroplane is flying at a constant horizontal velocity of 600 km/hr at an elevation of 6 km towards a point directly above the target on the earth's surface. At an appropriate time, the pilot releases a ball so that it strikes the target at the earth. The ball will appear to be falling
Which of the following spectrum has high to low frequency range?
A particle performs uniform circular motion with an angular momentum L. If the angular frequency of the particle is doubled and kinetic energy is halved, its angular momentum becomes.
Consider the following statements about dimensions
P:Force=acceleration due to gravity * mass
Q:Electric charge=current * time
R:Magnetic flux=Electric voltage * time
The correct statements are :
Force necessary to pull a circular plate of 5 cm radius from water surface for which surface tension is 75 dynes/cm,is
The total length of the circular plate on which the force will act = 2πR
Force to pull = 2πRT = 2 * π * 5 * 75 = 750π dynes
Density of a substance at 0ºC is 10gm/c.c and at 100º C its density is 9.7gm/c.c. The coefficient of linear expansion of the substance is
The resistance of the filament of an electric bulb changes with temperature. If an electric bulb rated 220 volt and 100 watt is connected (220 x 0.8) volt sources, then the actual power would be
Ist case - resistance is fixed
IInd case - resistance is not fixed →
Even Carnot engine cannot give 100% efficency because we cannot
Which of the two have same dimensions
If a star is moving towards the earth, then the spectrum lines are shifted towards
A wave y = a sin (ωt - Kx) on a string meets with another wave producing a node at x = 0. Then the equation of the unknown wave is
A 50 g bullet moving with velocity 10 m/s strikes a block of mass 950 g at rest and gets embedded in it. The loss in kinetic energy will be
Hydrogen bonding is maximum in
Cyanohydrin of which of the following will yield lactic acid?
Which one of the following substances will decolourise alkaline KMnO4 solution?
Benzene is used in the preparation of
In qualitative analysis NH₄Cl is added before NH₄OH
Which of the following has the smallest heat of hydrogenation per mole?
Conjugated double bond being most stable has the least heat of hydrogenation
Which quantum number is sufficient to describe the electron in hydrogen atom?
The disaccharide present in milk is
The number of sp3 hybrid carbons in 2-butyne is
Electrolysis of aqueous solution of CH₃COOK gives
Among the compounds BF3, NCl3, H2S, SF4 and BeCl2, identify the ones in which the central atom has the same type of hybridisation.
When water is added to quick lime,the reaction is
The equilibrium constant for the following reaction will be 3 A + 2 B → C
If the concentration of a reactant 'A' is doubled and the rate of its reaction increases by a factor of 2, the order of reaction with respect to 'A' is
If an endothermic reaction is non-spontaneous at freezing point of water and becomes feasible at its boiling point, then
2, 4, 6-Trinitrophenol is a/an
A compound with molecular formula C₇H₁₆ shows optical isomerism , the compound will be
Given that Eº(Zn2⁺/Zn) = - 0.763 and Eº (cd2⁺/cd) - 0.403 V, the emf of the following cell is Zn/Zn2⁺ ∣∣cd2⁺/cd is given by
Which of the following isoelectronic ions has the lowest ionisation enthalpy?
The size of anion is always larger than the cation or corresponding atom. As the distance of the outer electrons from the nucleus increases, the attractive force on the outer electrons decreases. Hence, the ionisation enthalpy is lowest for S2 − .
50 ml of hyffuses out through a small hole from a vessel in 20 minutes, time needed for 40 ml of oxygen to diffuse out is
Ozonolysis of 1,3-butadiene gives
An example of salt that will not hydrolyse is
The molecular formula of a saturated compound is C2H4Cl2. The formula permits the existence of two :
The ages of most ancient formations are estimated by
Which one gives carbylamine reaction ?
(with maximum yield) of this reaction by single S E reaction is:
An organic compound 'X' on treatment with acidified K₂Cr₂O₇ gives a compound 'Y' which reacts with I₂ and sodium carbonate to form Triodomethane. The compound 'X' is
Of the following which is a step growth polymer
The best method to separate the mixture of ortho and para nitrophenol (1:1) is
In the conversion Br₂ → BrO₃- the oxidation state of bromine changes from
A match box exhibits
The crystal system of a compound with unit cell dimensions a = 0.387; b = 0.387; c = 0.504 nm and α = β = 90º; γ = 120º is
Osmotic pressure of a solution is 0.0821 atm at a temperature of 300 K. The concentration in mole/litre will be
Which of the following is a hydrophilic colloidal sol?
A balanced chemical reaction is in accordance with
The sides of an equilateral triangle are increasing at the rate of 2 cm/sec. The rate at which the area increases, when the side is 10 cm is
The area bounded by the parabola y2 = 4ax and x2 = 4ay is
The equation of the chord of the circle x2 + y2 = 25 with (1, -1) as the mid point is
Points A(-4,-1), B(-2,-4), C(4,0) and D(2,3) are vertices of a
If x is positive, then the first negative terms in the expansion of is
The equation of an ellipse whose one focus is (4,0) and eccentricity is 4/5 is
If R → R is continuous such that f (x + y) = f (x) + f (y) , ∀x ∈ R , y ∈ R , and f(1) = 2 then f(100) =
2x - y - 2z = 2, x - 2y + z = -4, x + y + λz = 4 then the value of λ such that system of equations has no solutions is
If f(x) is intergrable on [0, a] then
A particular integral of the differential equation d2y/dx2+ a2y=sin ax is :
If f(x)=logx2log(x), then at x=e, f'(x)=
A is a square matrix satisfying the equation A2 − 4A − 5I = O . Then A−1 =
If cos⁻1x+cos⁻1y+cos⁻1z = 3π then xy + yz + zx is equal to
If A and B both are of order 2 x 3 , which one of these is not defined ?
The first quartile derived from a set of observations is 27 and its quartile deviation is 17. What is its third quartile?
Let f(x) = a x + x2. If it has a maximum at x = -3 then a is
Which measure of dispersion can be calculated in case of open end intervals?
The angle between lines joining origin and intersection points of line 2x+y=1 and curve 3x2+4xy-4x+1=0 is
n persons sit on a round table. The odd two against two specified persons sitting together, is
A polygon has 44 diagonals. The number of its sides is
In a class of 100 students, 55 students have passed in Mathematics and 67 students have passed in physics. Then the number of students who have passed in physics only is
Every term of a G.P. is positive and also every term is the sum of two preceding terms. Then the common ratio of the G.P. is
If p (q − r) x2 + q(r − p) x + r (p − q) = 0 has equal roots then 2/q =
If in a triangle ABC, if tan then the sides a, b, c are in
a, b, c, are in AP
If y = is equal to
The sides of a parallelogram are lx + ny + n = 0, lx + my + n' = 0, mx + ly + n = 0, mx + ly + n' = 0, the angle between its diagonals is
The equation sinx + siny + sinz = -3 for 0≤x≤2π, 0≤y≤2π, 0≤z≤2π, has
If A lies in the 2nd quadrant and 3 tan A+4=0 then the value of 2 cot A-5 cos A+sinA is equal to
A coin is tossed 3 times. The probability of getting head once and tail two times is
The length of the sub normal to the parabola y2=4ax at any point is equal to
The angle between the vectors
î - ĵ + k̂ and î + 2ĵ + k̂ is
Vectors 2i+3j-4k and ai+bj+ck are perpendicular, when