List of practice Questions

In dipositive zinc ion, the number of electrons with \(l=1,\;m=0\) is \(x\), and the number of electrons with \(l=2,\;m=-1\) is \(y\). The sum \(x+y\) is equal to:

Identify the option in which elements are correctly arranged in the increasing order of their electronegativity values.

Identify the correct sets of inner transition elements. \[ \text{I. } \mathrm{Nb,\ W,\ Sg} \] \[ \text{II. } \mathrm{Hs,\ Mt,\ Ds} \] \[ \text{III. } \mathrm{Tb,\ Dy,\ Cf} \] \[ \text{IV. } \mathrm{Nd,\ Bk,\ Es} \] The correct answer is (only):

In which of the following sets, the central atom of both the molecules does not obey the octet rule? \[ \text{I. } \mathrm{SF_4,\ XeF_4} \] \[ \text{II. } \mathrm{SCl_2,\ H_2S} \] \[ \text{III. } \mathrm{SnCl_2,\ XeO_3} \] The correct answer is (only):

The ratio of number of bonding electrons to antibonding electrons in \(O_2^+\) is:

If the speed of the electron in an orbit of hydrogen atom is \(\frac{1}{548}\) times the speed of light in vacuum, then the angular momentum of the electron in this orbit is (h - Planck's constant):

If \(E\) is the kinetic energy of the alpha particle emitted in the decay of a radioactive nucleus of mass number \(A\), then the disintegration energy released in the process is (Parent nucleus is at rest):

The correct statement regarding neutrino is:

In the given circuit, if the forward biased resistance of each diode is \(20\,\Omega\) and the reverse biased resistance of each diode is infinity, then the value of current \(I\) is:

In common emitter configuration of a transistor, if the change in collector current is \(99.5\%\) of the change in emitter current, then the common emitter current amplification factor is:

The combination of a receiver and a transmitter in electronic communication systems is:

A cyclotron with dees of radius \(50\text{ cm}\) and magnetic field \(1.5\text{ T}\) is used to accelerate protons and alpha particles separately. The ratio of the maximum kinetic energies acquired by proton and alpha particle is:

A magnet suspended in the horizontal plane makes 24 oscillations per minute at a place A where the dip angle is \(30^\circ\) and \(n\) oscillations per minute at another place B where the dip angle is \(60^\circ\). If the ratio of the horizontal components of earth's magnetic field at places A and B is \(16:9\), then the value of \(n\) is:

The relation between the total magnetic flux linked with a coil of resistance \(48\Omega\) and time is \(\phi=5-24t\). If there is no heat loss and the heat capacity of the coil is \(5\text{ JK}^{-1}\), then the rise in temperature of the coil during \(t=3\text{ s}\) to \(t=5\text{ s}\) is:

A parallel plate capacitor of capacitance \(5\,\mu\text{F}\) is connected to an AC source. If the relation between the potential difference \(V\) (in volt) across the plates of the capacitor and time \(t\) (in second) is \[ V=7\cos(100\pi t), \] then the displacement current between the plates of the capacitor at a time of \(5\,\text{ms}\) is:

In Young's double slit experiment, if the light of wavelength \(6000\AA\) is used, the fringe width is \(\beta\). If \(I\) is the intensity of light at a point on the screen where the path difference becomes \(2000\AA\), then the intensity of light at a point on the screen which is located at a distance of \(\frac{\beta}{6}\) from the central maximum is:

When two electric charges are placed at a distance apart in air, the electrostatic force between them is \(400\text{ N}\). If \(\frac13\) of the space between the two charges is filled with a medium of dielectric constant \(4\), then the electrostatic force between them is:

The electric potentials at two points A and B are \(+60\text{ V}\) and \(-30\text{ V}\) respectively. If a particle of mass \(20\,\mu\text{g}\) and charge \(+10\,\mu\text{C}\) is released from rest at point A, then the velocity with which the particle reaches point B is:

When a current of \(3\text{ A}\) flows through a uniform copper wire of radius \(0.6\text{ mm}\), the average drift speed of the electrons is \(V\). If \(1.5\text{ A}\) current is flowing in another uniform copper wire of radius \(1.2\text{ mm}\), then the average drift speed of the electrons is:

One end of a metal wire of length \(100\text{ cm}\) and radius \(0.6\text{ mm}\) is attached to an end of another wire made of the same metal of length \(180\text{ cm}\) and radius \(0.9\text{ mm}\). If the free end of the longer wire is kept at a potential of \(20\text{ V}\) and the free end of the shorter wire is kept at a potential of \(2\text{ V}\), then the potential at the junction of the two wires is:

If the angular momentum of an electron revolving in a circular orbit is \(2.1\times10^{-34}\text{ Js}\), then the magnetic moment associated with the electron is (Specific charge of electron \(=1.76\times10^{11}\text{ C kg}^{-1}\)):

In a Carnot engine, the heat released to the sink is \(22\%\) less than the heat taken from the source. If the temperature of the source is \(127^\circ\text{C}\), then the temperature of the sink is:

The number of gas molecules per unit volume in a vessel is \(2\times10^{25}\text{ m}^{-3}\) and the surface area of each gas molecule is \(12.5\sqrt{2}\times10^{-20}\text{ m}^2\). If all the gas molecules are in motion, then the mean free path of the gas molecules (in \AA) is:

Two wires A and B made of the same material have equal lengths. If the volumes of wires A and B are in the ratio \(1:8\) and the tensions applied to the wires A and B are in the ratio \(1:2\), then the ratio of the speeds of transverse waves in wires A and B is:

Second harmonic of an open pipe and third harmonic of a closed pipe of length \(75\text{ cm}\) produce \(n\) beats per second. If the fundamental frequency of the open pipe is \(167\text{ Hz}\), then the value of \(n\) is (Speed of sound in air \(=340\text{ ms}^{-1}\)):