An emf of 20 V is applied at time t = 0 to a circuit containing in series 10 mH inductor and 5 $$\Omega$$ resistor. The ratio of the currents at time t = $$\infty$$ and at t = 40 s is close to : (Take e2 = 7.389)

An inductance coil has a reactance of 100 $$\Omega$$. When an AC signal of frequency 1000 Hz is applied to the coil, the applied voltage leads the current by 45o. The self-inductance of the coil is

An amplitude modulated wave is represented by the expression vm = 5(1 + 0.6 cos 6280t) sin(211 × 104 t) volts The minimum and maximum amplitudes of the amplitude modulated wave are, respectively

Given the masses of various atomic particles mp = 1.0072 u, mn = 1.0087 u, me = 0.000548 u, $$m_{\overline{v}}$$ = 0, md = 2.0141 u, where p $$\equiv$$ proton, n $$\equiv$$ neutron, e $$\equiv$$ electron, $$\overline{v}$$ $$\equiv$$ antineutrino and d $$\equiv$$ deuteron. Which of the following process is allowed by momentum and energy conservation?

You are given that Mass of $${}_3^{7}Li$$ = 7.0160u, Mass of $${}_2^{4}He$$ = 4.0026u and Mass of $${}_1^{1}H$$ = 1.0079u. When 20 g of $${}_3^{7}Li$$ is converted into $${}_2^{4}He$$ by proton capture, the energy liberated, (in kWh), is : [Mass of nucleon = 1 GeV/c2]

A radioactive nucleus decays by two different processes. The half life for the first process is 10 s and that for the second is 100 s. The effective half life of the nucleus is close to :

Activities of three radioactive substances A, B and C are represented by the curves A, B and C, in the figure. Then their half-lives {T_{{1 \over 2}}}\left( A \right) : {T_{{1 \over 2}}}\left( B \right) : {T_{{1 \over 2}}}\left( C \right) are in the ratio :

Find the Binding energy per neucleon for $${}_{50}^{120}Sn$$. Mass of proton mp = 1.00783 U, mass of neutron mn = 1.00867 U and mass of tin nucleus mSn = 119.902199 U. (take 1U = 931 MeV)

Hydrogen ion and singly ionized helium atom are accelerated, from rest, through the same potential difference. The ratio of final speeds of hydrogen and helium ions is close to :

In a radioactive material, fraction of active material remaining after time t is 9/16. The fraction that was remaining after t/2 is

The time period of revolution of electron in its ground state orbit in a hydrogen atom is 1.6 $$\times$$ 10-16 s. The frequency of revolution of the electron in its first excited state (in s-1) is :

The activity of a radioactive sample falls from 700 s–1 to 500 s–1 in 30 minutes. Its half life is close to:

The graph which depicts the results of Rutherford gold foil experiment with $$\alpha$$-particales is : $$\theta$$ : Scattering angle Y : Number of scattered $$\alpha$$-particles detected (Plots are schematic and not to scale)

The energy required to ionise a hydrogen like ion in its ground state is 9 Rydbergs. What is the wavelength of the radiation emitted when the electron in this ion jumps from the second excited state to the ground state ?

In a reactor, 2 kg of 92U235 fuel is fully used up in 30 days. The energy released per fission is 200 MeV. Given that the Avogadro number, N = 6.023 $$\times$$ 1026 per kilo mole and 1 eV = 1.6 × 10–19 J. The power output of the reactor is close to

In a hydrogen atom the electron makes a transition from (n + 1)th level to the nth level. If n >> 1, the frequency of radiation emitted is proportional to :

The radius R of a nucleus of mass number A can be estimated by the formula R = (1.3 $$\times$$ 10–15)A1/3 m. It follows that the mass density of a nucleus is of the order of : (Mprot. $$\cong$$ Mneut $$\simeq$$ 1.67 $$\times$$ 10–27 kg)

A bullet of mass 5 g, travelling with a speed of 210 m/s, strikes a fixed wooden target. One half of its kinetic energy is converted into heat in the bullet while the other half is converted into heat in the wood. The rise of temperature of the bullet if the specific heat of its material is 0.030 cal/(g – oC) (1 cal = 4.2 × 107 ergs) close to :

An ideal gas in a closed container is slowly heated. As its temperature increases, which of the following statements are true? (A) the mean free path of the molecules decreases. (B) the mean collision time between the molecules decreases. (C) the mean free path remains unchanged. (D) the mean collision time remains unchanged.

Match the thermodynamic processes taking place in a system with the correct conditions. In the table : $$\Delta$$Q is the heat supplied, $$\Delta$$W is the work done and $$\Delta$$U is change in internal energy of the system. .tg {border-collapse:collapse;border-spacing:0;} .tg td{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; overflow:hidden;padding:10px 5px;word-break:normal;} .tg th{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; font-weight:normal;overflow:hidden;padding:10px 5px;word-break:normal;} .tg .tg-c3ow{border-color:inherit;text-align:center;vertical-align:top} Process Condition (I) Adiabatic (1) $$\Delta$$W = 0 (II) Isothermal (2) $$\Delta$$Q = 0 (III) Isochoric (3) $$\Delta$$U $$\ne$$ 0, $$\Delta$$W $$\ne$$ 0, $$\Delta$$Q $$\ne$$ 0 (IV) Isobaric (4) $$\Delta$$U = 0