Na2CO3 does not decompose on heating whereas CaCO3 decomposes, why?
Among PCl3 & PF3 which is having greater bond angle and why?
CO2 has got dipole moment of zero why?
The solubility of the hydroxides of the alkaline earth metals increases i.e. Ba(OH)2 has got a higher solubility in water compared to Mg(OH)2?
The melting point of KCl is higher than that of AgCl though the crystal radii of Ag+ and K+ ions are almost same.Why?
Out of H2O and H2S which is having greater bond angle and why?
Explain why the bond angle of H2O is 104° while that that of F2O is 102°?
Why bond angle in NH3 is 107° while in H2O it is 104.5°. Though the central atom in both the molecules is sp3 hybridized.
Why the bond angle of H–C–H in methane(CH4) is 109° 28’ while H–N–H bond angle in NH3 is 107° though both carbon and nitrogen are sp3 hybridized.
Classify the following bonds as ionic, polar covalent or covalent and give your answer:
(a) Si - Si bond in 
(b) Si - Cl bond in
(c) Ca - F bond in CaF2
(d) N - H bond in NH3
Calculate the minimum and maximum number of electrons which may have magnetic quantum number, m = +1 and spin quantum number s = - 1/2 in chromium(Cr):
Graphite is a soft solid lubricant extremely difficult to smelt. The reason for this anomalous behaviour is that graphite?
Two particles of mass 4kg and 6kg are seperated by a distance of 20m they are moving towards each other under mutual force of attraction the centre of mass is
A circular disc of radius 20cm is cut from one edge of larger disc of radius 50cm the shift in centre of mass
A gas at ntp is suddenly compressed to 1/4th of its org vol if gamma is supported to be 3/2 then final pressure is
Boron compounds behave as Lewis acid because of?
it takes 2s for a sound wave to travel b/w 2 fixed points when day temp is 10deg cal if temp rise to 30 deg cal sound wave travels b/w same fixed points
Let a relation be defined on a set of functions defined on R R such that R = {(f, g)|f – g is an even function} then, relation R is?
Out of N, O, Ne, Na, Na+, select the species which have maximum and minimum ionization energy?
The conversion of ozone into oxygen is exothermic under what conditions is ozone is most stable?
A uniform solid hemisphere of radius 10 m and mass 64 kg is placed with its curved surface on the smooth horizontal surface and a string AB of length 4m is attached to point A on its rim as shown in the figure. Find the tension in the string if hemisphere is in equilibrium.
A uniform rod of mass M and length L is free to rotate about a frictionless pivot located L/3 from one end. The rod is released from rest incrementally away from being perfectly vertical, resulting in the rod rotating clockwise about the pivot. When the rod is horizontal, what is the magnitude of the tangential acceleration of its center of mass?
A triangular frame consists of three identical rods, each of mass m and length l. It rests upright on a horizontal smooth surface with its lower right corner against a stop about which the frame could pivot. A horizontal force of magnitude F is applied to the upper corner of the frame as shown in the figure. What is the largest value of F may have without causing the frame to pivot upward about the stop?
A uniform, solid cylinder having mass M and radius R is pulled by a horizontal force F acting through the center as shown. The cylinder rolls to the right without slipping. What is the magnitude of the force of friction between the cylinder and the ground?
If a is square matrix of order 3 such that adja=64 find |a|
wave equation y= 0.08 sin 2pi/lambda[200t-x]
find velocity of wave
A parachutist drops freely from an aeroplane for 8s before the parachute opens out.then he descends with a retardation of 2ms reaching the ground with a velocity of 6ms.find the height from which he falls
A ball of density p0 falls from rest from point P onto the surface of a liquid of density p0 in time T. It enters the liquid stops moves up and returns to P in a total time 3T. Neglect viscosity, surface tension and splashing. The ratio p/p0 is equal to
An engine whistling at a constant frequency n0 and moving with a constant velocity goes past a stationary observer. As the engine crosses him, the frequency of the sound heard by him changes by a factor f. The actual difference in the frequency of the sound heard by him before and after the engine across him is
A flat coil of area A and n turns is placed at the centre of a ring of radius r (r2 >> A) and resistance R. The two are co-planar when current in the coil increases from zero to i, the total charge circulating in the ring is?
2 masses of 4kg and 6kg kept at a distance of 2m.Where the 3rd mass be placed,the gravitational be zero
Calculate the fringe width for light of wavelength 550 nm in a Young's slit experiment where the double slits are separated by 0.75 mm and the screen is placed 0.80 m from them.
Sample of 2,3 dibromopentane is heat in zinc dust the resulting compound is isolated and heated with hi in presence of p to yield---------
In a crystal structure of an element, atoms are present in ccp arrangement and tetrahedral voids, which of the following relation between the atomic radius and edge length is correct for the unit cell which is formed in this arrangement? (a is the edge length and R is the radius of atom)
The normal at P to a hyperbola of eccentricity e, intersects its transverse and conjugate axes at L and M respectively. If locus of the mid-point of LM is hyperbola, then eccentricity of the hyperbola is?
The focal length of the objective of a microscope is 2cm.The final image of object placed 3cm from the objective is formed at least distance of the distinct vision.if the magnifying power is 10 then calculate focal length of eyepiece.
The number of ordered pairs (x, y) of real numbers satisfying 
is equal to ?
The pH of a H2 SO4 solution is 2. The pH of this solution, if equal volume of 0.2 M NaCl solution is added to it, will be:
A copper rod of length L and mass m is sliding down a smooth inclined plane of inclination 
with a constant speed v. A current I is flowing in perpendicular to the plane of diagram inwards. A vertically upward magnetic field B exists in this region. The magnitude of the required magnetic B is?
A body oscillates with amplitude of 10 cm in a horizontal platform. The maximum angular frequency which the platform can vibrate vertically such that body of mass 10 kg will not leave contact is
A long Sighted can see distinctly object beyond 1 m.Calculate the power of less for the this person for normal vision?
A uniform circular disc of masss 12 kg is held by 2 identical springs when disc is pressed down slightly and released it executes shm with time period of2 s the force constant of each spring is [2 spring in parallel]