Practice Test

Q1) We have a source of red light and a blue light of same power. Then the red light gives photons per second Show Answer

Q2) The total energy E of the electron in a hydrogen atom is Show Answer

Q3) It is found experimentally that 13.6 eV energy is required to separate a hydrogen atom into a proton and an electron. The orbital radius is Show Answer

Q4) The wavelength of the second spectral lines in the Lyman series of the hydrogen spectrum is Show Answer

Q5) What is the shortest wavelength present in the Paschen series of the spectral lines ? Show Answer

Q6) A hydrogen atom initially in the ground level absorbs a photon which excites it to the n = 4 level. The wavelength of the photon is Show Answer

Q7) A 12.5 eV electron beam is used to bombard gaseous hydrogen at room temperature. What series of spectral lines will be emitted. Show Answer

Q8) When a hydrogen atom is raised from the ground state to an excited state Show Answer

Q9) According to Bohr's theory the radius of orbit described by principal quantum number n and atomic number Z is proportional to Show Answer

Q10) The ratio between kinetic energy and total energy of the electron of hydrogen atom, according to Bohr's model is Show Answer

Q11) In which of the following transitions will the wavelength be minimum ? Show Answer

Q12) The series limit wavelength of the Lyman series for hydrogen atom is give by Show Answer

Q13) Which of the following is true ? Show Answer

Q14) Pick out the statement which is true Show Answer

Q15) Fusion reaction takes place at high temperature because Show Answer

Q16) Statement 1 : Ionisation energy of atomic hydrogen is greater than atomic deuterium.
Statement 2 : Ionisation energy is proportional to reduced mass
Show Answer

Q17) Statement 1 : Nuclear energy is due to difference in sum of masses of component nucleons and the nucleus.
Statement 2 : Mass of nucleus is more than the sum of masses of component nucleons.
Show Answer

Q18) What are number of nuclei of C, when number of nuclei of A and B are equal ? Show Answer

Q19) At what time rate of disintegration of A and B are equal ? Show Answer

Q20) Which of the following process represents a gamma-decay ? Show Answer

Q21) The masses of neutron and proton are 1.0087 amu and 1.0073 amu respectively. If the neutrons and protons combine to form a helium nucleus ( alpha particles ) of mass 4.0015 amu, the binding energy of the helium nucleus will be ( 1 amu = 931 MeV) Show Answer

Q22) Statement 1 : In radioactive disintegration electron is emitted by nucleus.
Statement 2 : Electrons are always present inside nucleus.
Show Answer

Q23) What is the initial state of electron in hydrogen atom ? Show Answer

Q24) In final state : Show Answer

Q25) As the electron pimps, the ratio of its energy in the final state to initial state is Show Answer

Q26) The mass number of a nucleus is Show Answer

Q27) The ratio of the speed of an electron in the ground state in Bohr's first orbit of hydrogen atom to velocity of light in air is Show Answer

Q28) The energy required to remove an electron in a hydrogen atom from the state corresponding to n = 10 is Show Answer

Q29) The energy of the electron in the ground state of Hydrogen atom is -13.6 eV. The energy of the electron in the first excited state is Show Answer

Q30) The energy of an electron in the excited hydrogen atom is -3.4 eV. Then according to Bohr's theory, the angular momentum of the electron in that excited state is Show Answer

Q31) For an electron in the third orbit of Bohr Hydrogen atom, the moment of linear momentum is Show Answer

Q32) The energy of an excited hydrogen atom is -3.4 eV. The principal quantum number of the orbit is Show Answer

Q33) In a hydrogen atom, the total energy of an electron in a given orbit is -1.5 eV. The potential energy in the same oporbit is Show Answer

Q34) According to Bohr's atom model, the diameter of the first orbit of an electron in a hydrogen atom is Show Answer

Q35) For an hydrogen atom, the ratio of the area of the orbit of the first excited state of electron to the area of the orbit of the ground level is Show Answer

Q36) According to Bohr's theory, the energy of radiation emitted in the transition from the third excited state to the first excited state for a hydrogen atom is excited state for Show Answer

Q37) The ratio of the angular momenta of an electron in 13.6 eV the second and fifth Bohr orbit is Show Answer

Q38) When the orbital electron of a hydrogen atom goes from the ground state to a higher energy state, its velocity is reduced to one third of its initial value. If the radius of its orbit in the ground state is R, then the radius of the new orbit will be Show Answer

Q39) The ratio of the areas of the circular orbits of an electron in the ground state to that for the first excited state of an electron in the hydrogen atom is Show Answer

Q40) In Bohr atom model, the ratio of the periods of revolution of an electron in the orbits of first excited state and ground state is Show Answer

Q41) The ground state energy of hydrogen atom is - 13.6 eV. The energy needed to ionise H-atom from its second excited state is Show Answer

Q42) The energy of a hydrogen atom in the ground state is -13.6 eV. What is the energy required to raise an electron from the first orbit to the second orbit? Show Answer

Q43) If r is the radius of the orbit of the electron in the hydrogen atom, then its angular momentum is proportional to Show Answer

Q44) The ground state energy of hydrogen atom is - 13.6 eV. What is the P. E. of the electron in this state? Show Answer

Q45) The total energy of an electron in the first excited state of hydrogen atom is about-3.4 eV. What is its K.E. in this state? Show Answer

Q46) The minimum excitation potential of Bohr's first orbit in hydrogen atom Show Answer

Q47) The ratio of the areas of the electron orbits for the second excited state to the first excited state for the hydrogen atom is Show Answer

Q48) Which is the wrong statement from the following?
When an electron moves in the third Bohr orbit of a hydrogen atom. Show Answer

Q49) The momentum of a photon is p. The corresponding wavelength is Show Answer

Q50) What is the ratio of the energies of an hydrogen atom, when it is in the third and second excited states? Show Answer

Q51) The total energy of an electron in the first excited state of hydrogen atom is -3.4 eV. What are the values of its K.E. and P.E. in this state? Show Answer

Q52) When an orbital electron of the hydrogen atom is raised from the ground state to a higher energy state, its orbital speed reduces to half its initial value. If the radius of the initial electron orbit is r, then the new orbital radius will be Show Answer

Q53) If the electron in a hydrogen atom moves from ground state orbit to 5th orbit, then the potential energy of the system Show Answer

Q54) What is the minimum energy (in eV) required to remove an electron from the ground state level of a doubly ionized Li atom (Z = 3)? (Based on Bohr model) Show Answer

Q55) What is the radius of the second orbit of helium atom, on the basis of Bohr's atom model? Show Answer

Q56) For an electron moving in nth orbit of H-atom the angular velocity is proportional to Show Answer

Q57) Hydrogen atoms in the ground state are excited by monochromatic radiation photons of energy 12.1 eV. To which orbit the electron will be lifted, if a hydrogen atom absorbs the photon? Show Answer

Q58) The electron in the hydrogen atom jumps from the second orbit to the fourth orbit after absorbing photon. In this process Show Answer

Q59) The electron in a hydrogen atom makes a transition from an excited state to the ground state. Which one of the following statements is true? Show Answer

Q60) What is the moment of inertia of the electron moving in the second Bohr orbit of a hydrogen atom? Show Answer

Q61) For the hydrogen atom, the energy of radiation emitted in the transition from 4th excited state to 2nd excited state, according to Bohr's theory is Show Answer

Q62) The magnitude of the P.E. of the electron in the first orbit of the Bohr's atom is E. What is its K.E.? Show Answer

Q63) The orbital frequency of an electron in a hydrogen atom is proportional to (n is the principal quantum no.) Show Answer

Q64) In Bohr's orbit, kinetic energy of an electron in the nth orbit of an atom in terms of angular momentum is proportional to Show Answer

Q65) The ionisation energy of Hydrogen atom is 13.6 eV. What is the ionisation energy of He? Show Answer

Q66) A hydrogen atom in its ground state absorbs 10.2 eV of energy. What is the increase in its orbital angular momentum? Show Answer

Q67) The transition from the state n = 4 to n = 3 in a hydrogen like atom results in ultraviolet radiation. In which one of the following transitions, infrared radiations will be obtained? Show Answer

Q68) An electron accelerated through a potential difference of 4.9 V collides with a mercury atom and transfers it to the first excited state. What is the wavelength of radiation emitted in the transition of the mercury atom from its excited state to its normal state? Show Answer

Q69) What is the orbital acceleration of the electron in the first Bohr orbit of hydrogen atom? Show Answer

Q70) If r, v and E denote the radius of the orbit, speed of the electron and the total energy of the electron respectively in the Bohr model of hydrogen atom, then which of the following quantity is directly proportional to the quantum number n? Show Answer

Q71) The ionization energy of the electron in the hydrogen atom in its ground state is 13.6 eV. The atoms are excited to higher energy levels to emit radiations consisting of 6 wavelengths. Maximum wavelength of emitted radiation corresponds to the transition between Show Answer

Q72) An energy of 25.6 eV is required to remove one of the electrons from a neutral helium atom. What is the energy (in eV) required to remove both the electrons from a neutral helium atom? Show Answer

Q73) If the P.E. of a Bohr's hydrogen atom in the ground state is zero, then its total energy in the first excited state will be Show Answer

Q74) As per Bohr atom model, the minimum energy (in eV) required to remove an electron from the ground state of doubly ionised Lithium atom (Z = 3) is Show Answer

Q75) Which one is the wrong option from the following in the Bohr model of the hydrogen atom? Show Answer

Q76) A hydrogen-like atom of atomic number Z is in an excited state of quantum number n = 6. This excited atom makes a transition to the first excited state by successively emitting 2 photons of energies 10.2 eV and 17.00 eV respectively. What is the value of Z, if the ionisation energy of hydrogen is 13.6 eV? Show Answer

Q77) According to Bohr model the magnetic field at the centre (at the nucleus) of a hydrogen atom due to the motion of the electron in nth orbit is proportional to Show Answer

Q78) Suppose that the mass of an electron is doubled. How will it affect the Rydberg constant? Show Answer

Q79) An electron jumps from the fourth orbit to the second orbit of Hydrogen atom. The wave number of the radiations emitted by the electron is Show Answer

Q80) The ratio of the maximum to minimum wavelengths in Balmer series is Show Answer

Q81) The maximum number of photons emitted when an electron jumps from an energy level n = 5 to n = 1 is Show Answer

Q82) The ratio of the frequencies of the long wavelength limits of the Lyman and Balmer series of hydrogen is Show Answer

Q83) What is the ratio of the series limit of the Pfund series to that of the Lyman series in the emission spectrum of hydrogen? Show Answer

Q84) When an electron is an excited hydrogen atom, jumps from n = 4 to n = 2 level, green light is emitted. Which colour of light will be observed, if the electron jumps from n = 6 to n = 2? Show Answer

Q85) The wavelength of a line in a spectrum is inversely proportional to Show Answer

Q86) Ionisation potential of hydrogen atom is 13.6 eV. Hydrogen atoms in the ground state are excited by monochromatic radiation photons of energy 12.1 eV. How many spectral lines will be emitted by the hydrogen atom according to Bohr's theory? Show Answer

Q87) In a hydrogen atom, ultraviolet radiations are emitted when the electron jumps from Show Answer

Q88) In a hydrogen atom, infrared radiations are obtained in the transition of an electron from Show Answer

Q89) What is the ratio of the wavelengths of radiation emitted when an electron in the hydrogen atom jumps from the fourth orbit to the second orbit and from the third orbit to the second orbit? Show Answer

Q90) In hydrogen spectrum, as we go from Lyman series to Pfund series, the number of spectral lines Show Answer

Q91) A photon beam containing photons of various energies is passed through a sample of hydrogen like atoms, all the atoms being in the ground state. It was found that there were 4 dark lines in the absorption spectrum. What is the maximum number of lines that will be produced in the emission spectrum? Show Answer

Q92) The absorption transitions between the first and the fourth energy states of hydrogen atom are 3. The emission transitions between these states will be Show Answer

Q93) The ratio of longest wavelength and the shortest wavelength observed in the five spectral series of emission spectrum of hydrogen is Show Answer

Q94) When an electron jumps from n = 4 to n = 2 orbit in a hydrogen atom, we get, Show Answer

Q95) If an electron in hydrogen atom jumps from an orbit of level n = 3 to an orbit of level n = 2, the emitted radiation has a frequency (R = Rydberg's constant, C = velocity of light) Show Answer

Q96) Which of the following transitions in hydrogen atoms emit photons of highest frequency? Show Answer

Q97) Wavelengths of some of the lines emitted by H atoms are given below. Which line belongs to Lyman series? Show Answer

Q98) The longest wavelength in the ultraviolet region of the hydrogen spectrum is 120 nm. What is the smallest wavelength in the infrared region of the hydrogen spectrum? Show Answer

Q99) Which one of the following statements is true for nuclear forces? Show Answer

Q100) Which one of the following nuclear reaction is NOT possible? Show Answer

Q101) Which one of the following is a possible nuclear reaction? Show Answer

Q102) Which one of the following statements/reactions is correct? Show Answer

Q103) The mass density of a nucleus varies with mass number A as Show Answer

Q104) A nucleus ruptures into two nuclear parts, which have their velocity ratio equal to 2: 1. What will be the ratio of their nuclear size (or nuclear radii)? Show Answer

Q105) Which one is the correct equation? Show Answer

Q106) The mass defect in a particular nuclear reaction is 0.3 gram. What is the amount of energy liberated in the nuclear reaction in units of kilowatt hour? Show Answer

Q107) How much energy will be released, if a proton and an antiproton come very close to each other and annihilate? Show Answer

Q108) Heavy water is used as a moderator in a nuclear reactor. The function of the moderator is Show Answer

Q109) In nucleus fission process, energy is released because Show Answer

Q110) Fast neutrons can easily be slowed down by Show Answer

Q111) Which one of the following statement(s) is correct? Show Answer

Q112) From the following equations pick out the possible nuclear fusion reaction: Show Answer

Q113) During a negative beta decay Show Answer

Q114) Which is the most penetrating radiation out of the following? Show Answer

Q115) The 'rad' is the correct unit used to report the measurement of Show Answer

Q116) In a gamma ray emission from a nucleus Show Answer

Q117) Which one of the following radiations has the least wavelength? Show Answer

Q118) Which one of the following cannot be emitted by radioactive substances during their decay? Show Answer

Q119) Beta rays emitted by a radioactive material are Show Answer

Q120) The nuclei having the same number of protons but different number of neutrons are called Show Answer

Q121) In Bohr's theory of Hydrogen atom, the electron jumps from higher orbit 'n' to lower orbit 'p'. The wavelength will be minimum for the transition Show Answer

Q122) When an electron in a hydrogen atom revolves in stationary orbit, it Show Answer