KCET 2019

The frequency of an alternating current is \(50 \mathrm{~Hz}\). What is the minimum time taken by current to reach its peak value from rms value?

An inductor of inductance \(L\) and resistor \(R\) are joined together in series and connected by a source of frequency \(\omega\). The power dissipated in the circuit is

In Rutherford experiment, for head-on collision of \(\alpha\)-particles with a gold nucleus, the impact parameter is

Frequency of revolution of an electron revolving in \(n\)th orbit of \(\mathrm{H}\)-atom is proportional to

A hydrogen atom is ground state absorbs \(10.2 \mathrm{~eV}\) of energy. The orbital angular momentum of the electron is increased by

The end product of decay of \({ }_{90} \mathrm{Th}^{232}\) is \({ }_{82} \mathrm{~Pb}^{208}\). The number of \(\alpha\) and \(\beta\) particles emitted are respectively

Which one of the following nuclei has shorter mean life?

A capacitor of capacitance \(C\) charged by an amount \(Q\) is connected in parallel with an uncharged capacitor of capacitance \(2 C\). The final charges on the capacitors are

The equivalent capacitance between A and B is

During inelastic collision between two objects, which of the following quantity always remains conserved?

Two particles which are initially at rest move towards each other under the action of their mutual attraction. If their speeds are \(v\) and \(2 v\) at any instant, then the speed of centre of mass of the system is

Though the electron drift velocity is small and electron charge is very small, a conductor can carry an appreciably large current because

Masses of three wires of copper are in the ratio \(1: 3: 5\) and their lengths are in the ratio \(5: 3: 1\). The ratio of their electrical resistance are

Kirchhoff 's junction rule is a reflection of

In a potentiometer experiment, the balancing point with a cell is at a length \(240 \mathrm{~cm}\). On shunting the cell with a resistance of \(2 \Omega\), the balancing length becomes \(120 \mathrm{~cm}\). The internal resistance of the ce...

The readings of ammeter and voltmeter in the following circuit are respectively

In the given circuit, the current through 2\(\Omega\) resistor is

The variation of terminal potential difference \(V\) with current flowing through a cell is as shown. The emf and internal resistance of the cell are

An electron is moving with an initial velocity \(\mathbf{v}=v_0 \hat{\mathbf{i}}\) and is in a uniform magnetic field \(\mathbf{B}=B_0 \hat{\mathbf{j}}\). Then its de-Broglie wavelength

Light of certain frequency and intensity incident on a photosensitive material causes photoelectric effect. If both the frequency and intensity are doubled, the photoelectric saturation current becomes

A wire is stretched such that its volume remains constant. The poission's ratio of the material of the wire is

Consider the situation given in figure. The wire \(A B\) is slid on the fixed rails with a constant velocity. If the wire \(A B\) is replaced by a semicircular wire, the magnitude of the induced current will

An antenna uses electromagnetic waves of frequency \(5 \mathrm{~MHz}\).
For proper working, the size of the antenna should be

Due to Doppler's effect the shift in wavelength observed is \(0.1 \mathop A\limits^o\) for a star producing wavelength \(6000 \mathop A\limits^o\). Velocity of recession of the star will be

An electromagnetic wave is travelling in \(x\)-direction with electric field vector given by, \(\mathbf{E}_y=E_0 \sin (k x-\omega t) \hat{\mathbf{j}}\). The correct expression for magnetic field vector is

The phenomenon involved in the reflection of radio-waves by ionosphere is similar to

Two metal plates are separated by \(2 \mathrm{~cm}\). The potentials of the plates are \(-10 \mathrm{~V}\) and \(+30 \mathrm{~V}\). The electric field between the two plates is

Two protons are kept at a separation of \(10 \mathrm{~nm}\). Let \(F_n\) and \(F_e\) be the nuclear force and the electrostatic force between them

A certain charge \(2 Q\) is divided at first into two parts \(q_1\) and \(q_2\). Later the charges are placed at a certain distance. If the force of interaction between two chagrges is maximum then \(\frac{Q}{q_1}\) is

A particle of mass \(m\) and charge \(q\) is placed at rest in uniform electric field \(E\) and then released. The kinetic energy attained by the particle after moving a distance \(y\) is

An electric dipole is kept in non-uniform electric field. It generally experiences

A system of two charges separated by a certain distance apart stores electrical potential energy. If the distance between them is increased, the potential energy of the system

The figure gives the electric potential \(V\) as a function of distance through four regions on \(x\)-axis. Which of the following is true for the magnitude of the electric field \(E\) in these regions?

An aluminium sphere is dipped into water. Which of the following is true?

A cylindrical container containing water has a small hole at height of \(H=8 \mathrm{~cm}\) from the bottom and at a depth of \(2 \mathrm{~cm}\) from the top surface of the liquid. The maximum horizontal distance travelled by the water befo...

A satellite is orbiting close to the earth and has a kinetic energy \(K\). The minimum extra kinetic energy required by it just overcome the gravitation pull of the earth is

One mole of \(\mathrm{O}_2\) gas is heated at constant pressure starting at \(27^{\circ} \mathrm{C}\). How much energy must be added to the gas as to double its volume?

A thermodynamic system undergoes a cyclic process \(A B C\) as shown in the diagram. The work done by the system per cycle is

An object with mass \(5 \mathrm{~kg}\) is acted upon by a force, \(\mathbf{F}=(-3 \hat{\mathbf{i}}-4 \hat{\mathbf{j}}) \mathrm{N}\). If its initial velocity at \(t=0\) is $$\mathbf{v}=(3 \hat{\mathbf{i}}+12 \hat{\mathbf{j}}) \mathrm{m} / \m...

A magnetic needle has a magnetic moment of \(5 \times 10^{-2} \mathrm{~Am}^2\) and moment of inertia \(8 \times 10^{-6} \mathrm{~kgm}^2\). It has a period of oscillation of \(2 \mathrm{~s}\) in a magnetic field \(\mathbf{B}\). The magnitude...

A circular current loop of magnetic moment \(M\) is in a arbitrary orientation in an external uniform magnetic field \(\mathbf{B}\). The work done to rotate the loop by \(30^{\circ}\) about an axis perpendicular to its plane is

In a permanent magnet at room temperature

The trajectory of a projectile projected from origin is given by the equation \(y=x-\frac{2 x^2}{5}\). The initial velocity of the projectile is

The given graph shows the variation of velocity \(v\) with position \(x\) for a particle moving along a straight line

Which of the following graph shows the variation of acceleration a with position x?

A toroid has 500 turns per meter length. If it carries a current of \(2 \mathrm{A}\), the magnetic energy density inside the toroid is

In a cyclotron a charged particle

The number of turns in a coil of galvanometer is tripled, then

Coersivity of a magnet where the ferromagnet gets completely demagnetized is \(3 \times 10^3 \mathrm{~Am}^{-1}\). The minimum current required to be passes in a solenoid having 1000 turns per metre, so that the magnet gets completely demagn...

The magnetic fields at the centre O in the given figure is

A certain prism is found to produce a minimum deviation of \(38^{\circ}\). It produce a deviation of \(44^{\circ}\) when the angle of incidence is either \(42^{\circ}\) or \(62^{\circ}\). What is the angle of incidence when it is undergoing...