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?

Anonymous User Chemistry 23 Jun, 2019 1 Answer 107 views



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 ?

Rahul Kumar Chemistry 21 Jun, 2019 1 Answer 311 views




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

Jitendra Mishra Physics 17 Jun, 2019 1 Answer 74 views







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

Anonymous User Physics 05 Jun, 2019 0 Answer 67 views


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

Anonymous User Physics 05 Jun, 2019 1 Answer 79 views








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

Anonymous User Physics 30 May, 2019 1 Answer 140 views



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

Anonymous User Chemistry 28 May, 2019 1 Answer 1257 views




 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

Anonymous User Chemistry 22 May, 2019 1 Answer 91 views

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?

Preeti Rai Maths 20 May, 2019 1 Answer 174 views

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

Anonymous User Physics 20 May, 2019 1 Answer 244 views



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 ?

Anonymous User Physics 18 May, 2019 1 Answer 248 views







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 ?

Anonymous User Physics 12 May, 2019 1 Answer 108 views

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?

Anonymous User Physics 11 May, 2019 1 Answer 100 views


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?

Anonymous User Physics 09 May, 2019 1 Answer 165 views



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 ?

Anonymous User Physics 09 May, 2019 0 Answer 84 views