(Speed of light = 3 × 108 m/s Planck's constant = 6.63 × 10–34 Js Mass of electron = 9.1 × 10–31 kg)
Ne20 → 2He4 + C12
Given that the binding energy/ nucleon of Ne20, He4 and C12 are, respectively, 8.03 MeV, 7.07 MeV and 7.86 MeV, identify the correct statement:
(c = 3 × 108 ms–1, h = 6.6 × 10–34 J-s)
(hc = 12500 eV-Å)
(Assume the mass of electron to be m)
(Given h = 4.14 × 10–15 eVs and c = 3 × 108 ms–1)
A : Blue light
B : Yellow light
C : X-ray
D : Radiowave
|λ (μm) V0(Volt)|
| 0.3 2.0
Given that c = 3 × 108 ms–1 and e = 1.6 × 10–19 C, Planck’s constant (in units of J s) found from such an experiment is
(1 u = 931.5 MeV/c2), where c is the speed of light in vacuum)
The measured masses of the neutron, are 1.008665 u, 1.007825 u, 15.000109 u and 15.003065 u, respectively. Given that the radii of both the nuclei are same, 1 u = 931.5 MeV/c2 (c is the speed of light) and e2/(4πε0) = 1.44 MeV fm. Assuming that the difference between the binding energies of is purely due to the electrostatic energy, the radius of either of the nuclei is (1 fm = 10–15 m).
In the spectrum of hydrogen, the ratio of the longest wavelength in the Lyman series to the longest wavelength in the Balmer series is
|Column I||Column II|
|(A)||Nuclear fusion||(P)||Absorption on thermal neutrons by|
|(B)||Fission in a nuclear reactor||(Q)||nucleus|
|(C)||β−decay||(R)||Energy production in stars via hydrogen conversion to helium|
|(D)||γ-ray emission||(S)||Heavy water|
|List − I||List − II|
|(A)||Franck-Hertz Experiment.||(i)||Particle nature of light|
|(B)||Photo-electric experiment.||(ii)||Discrete energy levels of atom|
|(C)||Davison-Germer Experiment||(iii)||Wave nature of electron|
|(iv)||Structure of atom|
When the energy of the incident radiation is increased by 20%, the kinetic energy of the photoelectrons emitted from a metal surface increased from 0.5 eV to 0.8 eV. The work function of the metal is:
In the nuclear reaction the value of energy Q released is:
A pulse of light of duration 100 ns is absorbed completely by a small object initially at rest. Power of the pulse in 30 mW and the speed of light is 3 ×108 ms−1. The final momentum of the object is
The anode voltage of photocell is kept fixed. The wavelength λ of the light falling of the cathode is gradually changed. The plate current I of the photocell varies as follows:
In a hydrogen like atom election makes transition from an energy level with quantum number n to another with quantum number (n − 1). If n >> 1, the frequency of radiation emitted is proportional to:
Reason de-Broglie wavelength is inversely proportional to the mass of the object its velocity is constant.
The work functions of Silver and Sodium are 4.6 and 2.3 eV, respectively. The ratio of the slope of the stopping potential versus frequency plot for Silver to that of Sodium is
A freshly prepared sample of a radioisotope of half-life 1386 s has activity 103 disintegrations per second. Given that ln 2 = 0.693, the fraction of the initial number of nuclei (expressed in nearest integer percentage) that will decay in the first 80 s after preparation of the sample is
Reason Electron are present inside the nucleus.
The kinetic energy (in keV) of the alpha particle, when the nucleus at rest undergoes alpha decay, is
Match List I of the nuclear processes with List II containing parent nucleus and one of the end products of each process and then select the correct answer using the codes given below the lists:
A piece of iron is heated in a flame. It first becomes dull red then becomes reddish yellow and finally turns to white hot. The correct explanation for the above observation is possible by using:
The half life of a radioactive isotope ‘X’ is 20 years. It decays to another element ‘Y’ which is stable. The two elements ‘X’ and ‘Y’ were found to be in the ratio 1 : 7 in a sample of a given rock. The age of the rock is estimated to be:
A certain mass of Hydrogen is changed to Helium by the process of fusion. The Mass defect in fusion reaction is 0.02866 u. the energy liberated per u is:
(given 1u = 931 MeV)
For photoelectric emission from certain metal the cutoff frequency is v. If radiation of frequency 2v impinges on the metal plate, the maximum possible velocity of the emitted electron will be (m is the electron mass):
A parallel beam of fast moving electrons is incident normally on a narrow slit. A fluorescent screen is placed at a large distance from the slit. If the speed of the electrons is increased, which of the following statements is correct?
Three very large plates of same area are kept parallel and close to each other. They are considered as ideal black surfaces and have very high thermal conductivity. The first and third plates are maintained at temperatures and respectively. The temperature of the middle (i.e. second) plate under steady state condition is
A proton is fired form very far away towards a nucleus with charge e, where e is the electronic charge. It makes a closest approach of 10 fm to the nucleus. The de Broglie wavelength (in units of fm) of the proton at its stats is: (take the proton mass, ; J.s/C; ; )
where, n = 3, 4, 5...
Electron in hydrogen atom first jumps from third excited state to second excited state and then from second excited to the first excited state. The ratio of the wavelength emitted in the two cases is
Reason Charged particles on passing through a material medium loss their energy by causing ionisation of the atoms along their path.
A 200 W sodium street lamp emits yellow light of wavelength 0.6 m. Assuming it to be 25% efficient in converting electrical energy to light, the number of photons of yellow light it emits per second is.
If the radius of a star is R and it acts as a black body, what would be the temperature of the star, in which the rate of energy production is Q ?
A mixture consists of two radioactive materials A1 and A2 with half lives of 20s and 10s respectively. Initially the mixture has 40g of A1 and 160g of A2. The amount of the two in the mixture will become equal after:
An electron of a stationary hydrogen atom passes from the fifth energy level to the ground level. The velocity that the atom acquired as a result of photon emission will be :
If the anti-neutrino had a mass of 3 (where c is speed of light) instead of zero mass, what should be the range of the kinetic energy, K, of the electron?
In the Davisson and Germer experiment, the velocity of electrons emitted from the electron gun can be increased by
The wavelength of the first spectral line in the Balmer series of Hydrogen atom is 6561Å. The wavelength of the second spectral line in the Balmer series of singly − ionized helium atom is
The acivity of a freshly prepared radioactive sample is 1010 disintegration per second, whose mean life is 109 s. The mass j of the steel is . The mass (in mg) of the radioactive sample is.
Reason : An alpha particle carries four units of mass.
A silver sphere of radius 1 cm and work function 4.7 eV is suspended from an insulating thread in free −space. It is under continuous illumination of 200 nm wavelength light. As photoelectrons are emitted, the sphere gets charged and acquires a potential. The maximum number of photoelectrons emitted from the sphere is (where 1 < A< 10). The value of ‘Z’ is
To determine the half life of a radioactive element, a student plots a graph of versus t. Here is the rate of radioactive decay at time t. If the number of radioactive nuclei of this element decreases by a factor of p after 4.16 years, the value of p is
A diatomic molecule has moment of inertia I. By Bohr’s quantization condition its rotational energy in the nth level (n = 0 is not allowed) is
It is found that the excitation frequency from ground to the first excited state of rotation for the CO molecule is close to . Then the moment of inertia of CO molecule about its centre of mass is close to (Take h =)
Reason : The specific charge depends on charge and mass of positive ions present in positive rays.
Reason : β-particle and electron, both are similar particles.
Reason : If frequency of incident light is less than the threshold frequency, electrons are not emitted from metal surface.
An -particle and a proton are accelerated from rest by a potential difference of 100V. After this, their de Broglie wavelengths are respectively. The ratio, to the nearest integer is
What will be the ratio of their radii of the nuclei ?
Reason In a heavy nucleus, electrons are relatively close to nucleus.
If the mass of the particle is kg and a = 6.6nm, the energy if the particle in its ground state is close to
Assume that two nuclei in the core of fusion reactor at temperature T are moving towards each other, each with kinetic energy 1.5kT, when the separation between them is large enough to neglect coulomb potential energy. Also neglect any interaction from other particle in the core. The minimum temperature T required for them to reach a separation of m is in the range.
Results of calculations for four different designs of a fusion reactor using D-D reaction are given below. Which of these is most promising based on Lawson criterion?
Reason The spectrum of hydrogen atom is only absorption spectrum.
Photoelectric effect experiments are performed using three different metal plates and having work functions and respectively. A light beam containing wavelengths of 550 nm, 450 nm and 350 nm with equal intensities illuminates each of the plates. The correct I-V graph for the experiment is
This section contains 2 questions. Each questions contains statements given in two columns, which have to be matched. The statements in Column I are labelled A, B, C and D, while the statements in Column II are labelled, P, Q, R, S and T. Any given statement in Column I can have correct matching with one or more statement(s) in Column II. the appropriate bubbles corresponding to the answers to these questions have to be darkened as illustrated in the following example :
If the correct matches are A− P, S and T; B− Q and R; C−P and Q; and D− S and T; then the correct darkening of bubbles will look like the following.
Column II gives certain systems undergoing a process. Column I suggests changes in some of the parameters related to the system. Match the statements in Column I to the appropriate process(es) from Column II.
|Column I||Column II|
|(A)||The energy of the system is increased.||(p)||
System: A capacitor initially uncharged
Process: It is connected to a battery
|(B)||Mechanical energy is provided to the system, which is converted into energy of random motion of its parts||(q)||
System: A gas in an adiabatic container fitted with an adiabatic piston
Process : The gas is compressed by pushing the piston
|(C)||Internal energy of the system is converted into its mechanical energy||(r)||System: A gas in a rigid container Process: The gas gets cooled due to colder atmosphere surrounding it.|
|(D)||Mass of the system is decreased||(s)||System: A heavy nucleus initially at rest Process: The nucleus fissions into two fragments of nearly equal masses and some neutrons are emitted.|
System: A resistive wire loop
Process: The loop is placed in a time varying magnetic field perpendicular to its plane.
A radioactive sample S1 having an activity 5 has twice the number of nuclei as another sample S2 which has an activity of . The half lives of S1 and S2 can be
|(A)||Nuclear fusion||(P)||Converts some matter into energy|
|(B)||Nuclear fission||(Q)||Generally possible for nuclei with lower atomic number|
|(C)||β-decay||(R)||Generally possible for nuclei with higher atomic number|
|(D)||Exothermic nuclear reaction||(S)||Essentially proceeded by weak nuclear forces|
λ1 and λ2 are de Broglie wavelengths of the particle, when 0 ≤ x ≤ 1 and x > 1, respectively. If the total energy of particle is 2E0, find λ1/λ2.
(a) the atomic number of the nucleus.
(b) the frequency of Kα line of the X-ray produced. (R = 1.1 × 107 m−1 and c = 3 ×108 m/s)
(A) fA = fB and IA ≠ IB
(B) fA = fC and IA = IC
(C) fA = fB and IA = IB
(D) fB = fC and IB = IC
(a) the number of photoelectrons emitted up to t = 10 s,
(b) the magnitude of the electric field between the plates A and B at t = 10 s, and
(c) the kinetic energy of the most energetic photoelectron emitted at t =10 s when it reaches plate B.
(Neglect the time taken by the photoelectron to reach plate B. Take ε0 = 8.85×10−12 C2/N-m2)
(a) Find the atomic number of the atom.
(b) Calculate the smallest wavelength emitted in these transitions.
Take hc = 1240 eV-nm, ground state energy of hydrogen atom = −13.6 eV,)
(A) lH > lLi and |EH| > |ELi|
(B) lH = lLi and |EH| < |ELi|
(C) lH = lLi and |EH| > |ELi|
(D) lH < lLi and |EH| < |ELi|
(A) 400 μs
(B) 63 μs
(C) 40 μs
(D) 300 μs
(A) AXZ + Υ → AXZ - 1 + a + b
(B) AXZ +1n0 → A−3XZ - 2 + c
(C) AXZ → AXZ + f
(D) AXZ + e - 1 → AXA - 1 + g
(1 a.m.u. = 931.470 MeV/c2)
(A) inner orbits of atoms
(B) free electrons existing in nucleus
(C) decay of a neutron in a nucleus
(D) photon escaping from the nucleus
(A) 2 → 1
(B) 3 → 2
(C) 4 → 2
(D) 5 → 4
(A) λK – λC increases
(B) λK – λC decreases
(C) λK increases
(D) λK decreases