The electron of hydrogen atom was excited from ground state to a higher orbit. During de-excitation of the electron, photons of six different wavelengths were emitted. If each photon forms a spectral line, how many spectral line will be visible to naked eye?
What is the sum of the number of electrons with l = 0 and l = 2 present in Cu+ ion?
The ratio of masses of oxygen and nitrogen in a particular gaseous mixture is 1 : 4. The ratio of number of their molecule is ?
For the estimation of nitrogen, 1.4 g of an organic compound was digested by Kjeldahl method and the evolved ammonia was absorbed in 60 mL of M/10 sulphuric acid. The unreacted acid required 20 mL of M/10 sodium hydroxide for complete neutralization. The percentage of nitrogen in the compound is ?
The variance of first 50 even natural numbers is:
What is Human excretory system? explain?
When a rubber-band is stretched by a distance x, it exerts a restoring force of magnitude F = ax + bx*x where a and b are constants. The work done in stretching the unstretched rubber-band by L is ?
A parallel plate capacitor is made of two circular plates separated by a distance of 5 mm and with a dielectric of dielectric constant 2.2 between them. When the electric field in the dielectric is 10000 V/m, the charge density of the positive plate will be close to
The pressure that has to be applied to the ends of a steel wire of length 10 cm to keep its length constant when its temperature is raised by 100°C is ?
(For steel Young’s modulus is (2 × 10^11) N/m^2 and coefficient of thermal expansion is 1.1 × 10^-5 K^-1)
A block of mass m is placed on a surface with a vertical cross section given by
.
If the coefficient of friction is 0.5, the maximum height above the ground at which the block can be placed without slipping is ?
If 9th term of AP is 12 and 10the term is 18.what will be 18the term?
Calculate the moment of inertia of two dimensional rod?
Calculate the Moment of inertia of a ring?
The mi of a rod abt an axis through its axis and perpendicular to it is 1/12ml^2 the rod bent in middle so that 2 halves make angle 60 mi of bent rod abt same axis is
The straight thin uniform rod of length 4l and mass 4m is force to bent in shape of square.It moment of inertia of any side of the square is?
a square is made by joining 4 rods each of mass m and length its mi abt an axis pq in its plane and is passing through 1 of its end
Calculate the pH of an acetate buffer that is a mixture with 0.10 M acetic acid and 0.10 M sodium acetate?
A wheel of radius r rolls without slipping with a speed v on a horizontal road when it is at a pt a on road a small jump of mud separates from wheel at its highest point b and drops at c on road the dist ac [range] is
A wheel of moment of inertia 10 kgm2 is rotating a 10 rotation per min the work done in increasing its speed to 5 times its org value will be
ratio of ke and rotational energy in motion of disc is
for reaction ab[g] give rise to a[g]+b[g] .ab is 33% dissociated the total pressure of equilibrium system is p atm therefore p is related to kp is
on adding 100ml of 0.4 gl-1 of naoh to 500 ml sol of a buffer changed its ph by 0.5 what is the buffer capacity of buffer mixture
a block of mass 2 kg and specific gravity 5+2 is attached with springof spring constant=100n+mand is half dipped in water if extension is 1cm what is the force exerted by bottom of tank on block
A water drop of 0.05cm3 is squeezed between two glass plates and spreads into area of 40cm2. If the surface tension of water is
70 dyne/cm then the normal force required to separate the glass plates from each other will be
a fluid containercontaining a liquid of density p is accelerating a towards east if angle if inclination alpha of free surface is 37 deg then value of a will be
heat of neutralization of h2c2o4 is -26 kcal/mol the dissociation energy of h2c2o4 is
The equilibrium constant of the reaction CH3COOH (l)+C2H5OH (l)=CH3COOC2H5+H2O is 4.if one mole of each of acetic acid and ethyl alcohol are heated in presence of little concentrated H2SO4 at equilibrium the amount of ester present is
A drop of liquid of diameter 2.8 mm beaks up into 125 identical drops. The change in energy is nearly
(S.T. of liquid = 75 × 10-3 N/m)
On heating an aliphatic primary amine with chloroform and ethanolic potassium hydroxide, the organic compound formed is?
Let a, b, c and d be non−zero numbers. If the point of intersection of the lines 4ax + 2ay + c = 0 and 5bx + 2by + d = lies in the fourth quadrant and is equidistant from the two axes then?
an elemental crystal has a density of 8570kgm3 the packing efficiency is 0.68 if closest distance b/w neighbouring atom is 2.86 angstrom the mass of 1 atom
A bird is sitting on the top of a vertical pole 20 m high and its elevation from a point O on the ground is 45°. It flies off horizontally straight away from the point O. After one second, the elevation of the bird from O is reduced to 30°. Then the speed (in m/s) of the bird is?
There is a circular tube in a vertical plane. Two liquids which do not mix and of densities d1 and d2 are filled in the tube. Each liquid subtends 90° angle at centre. Radius joining their interface makes an angle α with vertical. Ratio of d1/d2
A pipe of length 85 cm is closed from one end. Find the number of possible natural oscillations of air column in the pipe whose frequencies lie below 1250 Hz. The velocity of sound in air is 340 m/s?
the mass of a uniform ladder of length 5m is 20 kg a person of mass 60 kg stand on ladder stand at a height of 2m from bottom position of centre of mass of ladder and man from bottom is
From a tower of height H, a particle is thrown vertically upwards with a speed U. The time taken by the particle, to hit the ground, is n times that taken by it to reach the highest point of its path. The relation between H, u and n is ?
The slope of the line touching both the parabolas
A ball of mass 1 kg bounces against grd approach vel=25 m/s andvel after hitting grd is 20 wht is impulse
Three positive numbers form an increasing G.P. If the middle term in this G.P. is doubled, the new numbers are in A.P. Then the common ratio of the G.P. is?
Let PS be the median of the triangle with vertices P(2, 2), Q(6, −1) and R (7, 3). The equation of the line passing through (1, −1) and parallel to PS is ?
Let C be the circle with centre at (1, 1) and radius = 1. If T is the circle centred at (0, y), passing through origin and touching the circle C externally, then the radius of T is equal to ?
Let α and β be the roots of equation px2 + qx + r = 0, p ≠ 0. If p, q, r are in A.P. and 1/α +1/ β = 4, then the value of |α − β| is
The radiation corresponding to 3 → 2 transition of hydrogen atom falls on a metal surface to produce photoelectrons. These electrons are made to enter a magnetic field of 3 × 10−4 T. If the radius of the largest circular path followed by these electrons is 10.0 mm, the work function of the metal is close to ?
A bird is sitting on the top of a vertical pole 20 m high and its elevation from a point O on the ground is 45°. It flies off horizontally straight away from the point O. After one second, the elevation of the bird from O is reduced to 30°. Then the speed (in m/s) of the bird is?
From a tower of height H, a particle is thrown vertically upwards with a speed U. The time taken by the particle, to hit the ground, is n times that taken by it to reach the highest point of its path.
The coercivity of a small magnet where the ferromagnet gets demagnetized is 3 × 10^3 A m−1 . The current required to be passed in a solenoid of length 10 cm and number of turns 100, so that the magnet gets de magnetised when inside the solenoid, is?
In a large building, there are 15 bulbs of 40 W, 5 bulbs of 100 W, 5 fans of 80 W and 1 heater of 1 kW. The voltage of the electric mains is 220 V. The minimum capacity of the main fuse of the building will be?
Four particles, each of mass M and equidistant from each other, move along a circle of radius R under the action of their mutual gravitational attraction. The speed of each particle is ?
A parallel plate capacitor is made of two circular plates separated by a distance of 5 mm and with a dielectric of dielectric constant 2.2 between them. When the electric field in the dielectric is 3 × 10^4 V/m, the charge density of the positive plate will be close to ?