An electron is moving at a velocity of 100 m/s along the X-axis in the presence of an electric field of 30 V/m directed along the Y-axis and a magnetic field of 300 G directed along the Z axis. The magnitude and direction of force acting on the electron is (Given: the charge on the electron is "e")

The ratio of nucleus density of nitrogen nucleus (\( {}^{14}_7\text{N} \)) to the nucleus density of oxygen nucleus (\( {}^{16}_8\text{O} \)) will be :

A magnetic field B exists in a direction perpendicular to the plane of a square loop made of metal wire. The wire has a diameter of 4 mm and a total length of 30 cm. The magnetic field B changes at a steady rate of \( 0.032 \text{ T s}^{-1} \). The induced current in the closed loop is\n(Given: Resistivity of the metal wire is \( \rho = 1.57 \times 10^{-8} \Omega \text{ m} \))

The reverse biasing in a p-n junction diode

The speed of propagation of light wave in a dispersive medium does NOT depend on the :

Choose the correct phase relationship between the current and the applied voltage in an a.c. circuit.
(A) In a pure resistive circuit, the current is in phase with the applied voltage.
(B) In a pure inductive circuit, the current lags behind the voltage by a phase angle of 90°.
(C) In a pure inductive circuit, the current leads the voltage by a phase angle of 90°.
(D) In a pure resistive circuit, the current is not in phase with the applied voltage.
Choose the correct answer from the options given below:

A bar magnet with pole strength m and magnetic dipole moment p is cut into two identical pieces along its length.
Then for each of the two pieces

Karyotype of an individual is 47, XXY. The individual is suffering from :

The rise in prices before Diwali is an example of:

The lines \(\frac{x}{1}=\frac{y}{2}=\frac{z}{3}\) and \(\frac{x-3}{-3}=\frac{y-4}{-6}=\frac{z-5}{-9}\) are :

Werner was the first to describe the bonding features in coordination compounds. But his theory could not answer basic questions like :
(i) Why only certain elements possess the remarkable property of forming coordination compounds ?
(ii) Why the bonds in coordination compounds have directional properties ?
(iii) Why coordination compounds have characteristics magnetic and optical properties ?Many approaches have been put forth to explain the nature of bonding in coordination compounds viz. Valence Bond Theory (VBT), Crystal Field Theory (CFT), Ligand Field Theory (LFT) and Molecular Orbital Theory (MOT).
We shall focus our attention on elementary treatment of the application of VBT and CFT to coordination compounds.
According to this theory, the metal atom or ion under the influence of ligands can use its ( \(n -1\) )d, ns np or ns, np, nd orbitals for hybridisation to yield a set of equivalent orbitals of definite geometry such as octahedral, tetrahedral, square planar and so on.
These hybridised orbitals are allowed to overlap with ligand orbitals that can donate electron pairs for bonding.
Predict the shape of \(\left[ Ni ( CO )_4\right]\) on the basis of VBT :

Choose the correct statements from the following :
(A) For a point charge, concentric spheres centred at the location of the charge are equipotential surfaces
(B) For practical purpose the earth is used as a reference at zero potential in electrical circuit
(C) In a cavity within a conductor without charges, the electric field is zero
(D) During charging by rubbing, the insulating material with higher work function becomes positively charged
(E) Dielectric polarisation means formation of electric dipole inside the dielectric
Choose the correct answer from the options given below :

The reverse osmosis occurs when