Nucleus Questions and Answers

If M M and M are the rest masses of electron proton and hydrogen atom in the ground state with energy 13 6 eV respectively which of the following is exactly true c is the speed of light in free space a M M M b M M M 13 6eV c c M M M M M K d M H 13 6eV 2 where K 13 6eV c or zero

52 If you were able to isolate two identical charged particles of mass m from all external forces a what would the charge of the particles have to be in terms of m and any necessary physical constants if the two particles remained at a fixed sepa ration from each other b Is it necessary that the charge on both the particles be equal c What is the minimum value of m so that they can be held in such a configuration d Com ment on the nature of equilibrium

The half life of a radioactive isotope X is 50 years It decays to another element Y which is stable The two elements X and Y were found to be in the ratio of 1 15 in a sample of a given rock The age of the rock was estimated to be 2011 a 200 yr c 100 yr b 250 yr d 150 yr

An a Rutherford scattering experiment when a projectile of charge z and mass M approaches a target nucleus of charge z and mass M the distance of closest approach is ro The energy of the projectile is 1 Directly proportional of mass M 2 Directly proportional of M x M X 3 Directly proportional of z Z 4 Inversely proportional to z

Fission of nuclei is possible because the binding energy 2005 per nucleon in them A a increases with mass number at high mass numbers b decreases with mass number at high mass numbers c increases with mass number at low mass numbers d decreases with mass number at low mass numbers

As the electron in Bohr orbit of hydrogen atom passes from state n 2 to n 1 the kinetic energy K and potential energy U change as 2015 a K two fold U four fold b K four fold U two fold c K four fold U also four fold d K two fold U also two fold

Curium 96 Cm 248 decays to plutonium 4 Pu244 emitting an a particle Assume that a particle was initially at the periphery of nucleus as shown in the following figure 94 e He Take the radius of spherical nucleus approximately equal to 1 31 x 10 14 m Assume that all the positive charge of the nucleus besides the a particle is at the centre of the nucleus Find the value of the ratio Initial PE of the a particle Q value of the reaction 95Cm248 248 072220 u 94Pu244 244 064100 u He 4 002603 u 1 u 931 MeV c rounded to nearest integer The masses involved in the decay are as follows

1 AL Five equal resistances each of resistance R are connected as shown in the Figure A battery of voltage V is connected between A and B The current flowing in AFCEB will be 1 2 3 4 V R V 2R 2V R 3V R R MMMM 4 R www E

Which shorter mean life dN dt A C B A C Same for all C B A t

5 Mark out the incorrect statement a A free neutron can transform itself into photon b A free proton can transform itself into neutron c In beta minus decay the electron originates fro nucleus

Which of the following parameters is same fo electron in all hydrogen like atoms and ions i their ground states 1 Radius Speed 3 Energy of atom Speed Energy 4 Speed Radius 2

unstable nucleus of mass M initially M at rest emits an element of mass The Q 50 value of this nuclear reaction is E What will be kinetic energy of emitted element in this process 1 3 E 50 E 2 49E 50 50 4 E

Two identical metal plates show photoelectric effect by a light of wavelength falling on plate A and A on plate B A2 The maximum kinetic energy is 1 2K Kg 2 K KB 2 3 KA 2KB 4 K Kg 2

The graph shows some measurements of the decay rate of a sample of radioactive nuclei 128L Find the half life for this radioactive nucleus loge R R in counts s 1 20 min 3 15 min 6 2 0 50 100 150 200 Time min 2 25 min AY 225 L

m In process of nuclear fission of 1 g uranium the mass lost is 0 90 mg The efficiency of power house s fission reactor is 20 To obtain 400 mega watt power from the power house how much uranium required per hour 1 88 g 3 44 g 2 178 g 4 39

1 If the frequency and intensity of light source are both doubled then the saturation photocurrent remains the same 2 A non monochromatic light is used in an experiment on photoelectric effect the stopping potential is related to the longest wavelength 3 When stopping potential is applied to a photoelectric experiment no photocurrent is observed because the emission of photoelectrons is stopped 4 The product of force and time has the same unit as that of Planck s constant