physical chemistry
JEE (MAIN+ADVANCED)
NURTURE COURSE
Exercise
Atomic Structure
(English Medium)
, ALLEN
® Atomic Structure
EXERCISE # S-I
FUNDAMENTAL PARTICLES
æqö
1. The ratio of specific charges ç ÷ of an a-particle and a deuteron is x : 1.00. The value of 'x' is.
èmø
AS0001
2. Specific charges of two particles A and B are in ratio 2 : 3. If their mass ratio mA : mB is 2 : 3, then the
æ qA ö
ratio of their charges ç ÷ is 4.00 : x. The value of 'x' is.
è qB ø
AS0002
3. Arrange electron (e), proton (p) , neutron (n) and a-particles (a) , in the increasing order of their e/m
ratio.
®
AS0003
4. In oil drop experiment, the following charges were experimentally determined for five oil droplets
1.20 × 10–18 unit, 3.00 × 10–18 unit, 6.00 × 10–18 unit, 2.40 × 10–18 unit and 3.60 × 10–18 unit (unit
is arbitrary). What should be the charge on electron in this arbitrary unit (in the order of 10–19) ?
AS0004
5. The kinetic energy of a charged particle (charge = q) accelerated by a potential difference of 10000
volt is 1.6 × 10–15 Joule. The value of 'q' (in 10–19 coulomb) is.
AS0005
RUTHERFORD'S ATOMIC MODEL
6. If the radius of an atom is 2Å and the radius of its nucleus is 4 × 10–15 m. The ratio of volume of
nucleus to that of atom is x : 1015. The value of 'x' is.
AS0006
7. Radius of nucleus may be given as RN = R0.A1/3 , where A = mass number and R0 = constant.
Calculate the density (in 1017 kg m–3) of nucleus of an atom if R0 = 1.2 × 10–15.
[NA = 6 × 1023, 23 × 8p × (1.2)3 = 1000]
AS0007
node06\B0BC-BD\Kota\JEE(Advanced)\Nurture\Chem\Module\4-Ideal-Reas-Atomic-Chemical Eq\Eng\3. Atomic\02. Ex.p65
8. The ratio of distances of closest approach of a proton and an a-particle projected towards the same
nucleus with the same initial kinetic energy is x : 1. The value of 'x' is.
AS0008
9. An a-particle of K.E. 5.4 MeV is projected towards Cr-nucleus (Z = 24). What is its distance of
closest approach (in 10–14 m) ? (e = 1.6 × 10–19C)
AS0009
10. With what speed (in 107 ms–1) an a-particle should be projected towards stationary krypton nucleus
(Z = 36) such that it approaches upto 2.4 × 10–14m from the nucleus ?
(NA = 6 × 1023, e = 1.6 × 10–19C).
AS0010
E 175
,JEE-Chemistry ALLEN
®
WAVE CHARACTERISTICS
11. Calculate the wave length (in nm) of an electromagnetic radiation of frequency 2 × 1015 Hz.
AS0011
12. A radiostation emits the radiations of wavelength 2000 m (meter band of station). What is the frequency
band of that station, in kHz (Frequency of emitted radio waves) ?
AS0012
13. The wave numbers of two electromagnetic radiations are 4 × 106 m–1 and 2 × 105 cm–1. The ratio of
their frequencies is x : 1.00. the value of 'x' is.
AS0013
14. An electromagnetic radiation makes 5000 waves in 20 cm. The frequency of radiation (in 1012 Hz)
®
is.
AS0014
PLANCK'S QUANTUM THEORY
15. Calculate the energy (in 10–19 Joule) of a photon of wave length 4000 Å.
AS0015
16. The eyes of certain member of the reptile family pass a single visual signal to the brain when the
visual receptors are struck by photons of wavelength 662 nm . If a total energy of 3.0 ´ 10 -18 J is
required to trip the signal, what is the minimum number of photons that must strike the receptor.
(h = 6.62 × 10–34 J × s)
AS0016
17. Find the number of photons (in the order of 1022) of radiation of frequency 5 × 1013 s–1 that must be
absorbed in order to melt one gm ice when the latent heat of fusion of ice is 330 J/g.
(h = 6.6 × 10–34 J × sec.)
AS0017
18. A certain dye absorbs 4000 Å and fluoresces at 5000 Å these being wavelengths of maximum
absorption that under given conditions 40% of the absorbed energy is emitted. If the ratio of the
node06\B0BC-BD\Kota\JEE(Advanced)\Nurture\Chem\Module\4-Ideal-Reas-Atomic-Chemical Eq\Eng\3. Atomic\02. Ex.p65
number of quanta emitted to the number absorbed is x : 1.00, the value of 'x' is.
AS0018
19. The reaction between H2 and Br2 to form HBr in presence of light is initiated by the photo decomposition
of Br2 into free Br atoms (free radicals) by absorption of light. The bond dissociation energy of Br2 is
192 KJ/mole. What is the longest wavelength (in nm) of the photon that would initiate the reaction.
æ eV ö
ç1 = 96kJ / mol ; hc = 1240 ev ´ nm ÷
è atom ø
AS0019
20. The quantum yield for decomposition of HI is 0.2. In an experiment 0.01 moles of HI are decomposed.
Find the number of photons (in the order of 1022) absorbed. (NA = 6 × 1023)
AS0020
176 E
, ALLEN
® Atomic Structure
PHOTOELECTRIC EFFECT
21. The minimum energy required for the emission of a metal electron is 1.324 × 10–18 J. Calculate the
threshold wavelength (in nm) required to eject the electron ?
AS0021
22. A light source of wavelength l illuminates a metal and ejects photo electron with (KE)max = 1 eV.
l
Another light source of wave length , ejects photoelectrons from same metal with (KE)max=5eV.
3
Find the value of work function (eV) of metal.
AS0022
23. The dissociation energy of H2 is 482.5 KJ/mol. If H2 is exposed to radiant energy of wavelength
124 nm, what % of radiant energy will be converted into K.E.
ev
(1 = 96.5 kJ/mol, hc = 1240 eV × nm)
®
atom
AS0023
24. The K.E. of an electron emitted from tungstan surface is 3.06 eV. What voltage (in volt) would be
required to bring the electron to rest.
AS0024
25. Stopping potential [V volts] is plotted against frequency of light used [u].
Find work function (eV). (h = 6.62 × 10–34 J × s)
V(Volt)
1 3 5
(u × 10 ) Hertz
14
AS0025
BOHR’S MODEL
26. If the mass of electron is doubled, then find the new radius (in Å) of 1st orbit of H-atom ?
AS0026
node06\B0BC-BD\Kota\JEE(Advanced)\Nurture\Chem\Module\4-Ideal-Reas-Atomic-Chemical Eq\Eng\3. Atomic\02. Ex.p65
27. If an electron in H-atom jumps from one orbit to other its angular momentum doubles. If the new
radius is 'x' times the old radius, then find x ?
AS0027
28. 5
The radius of the an orbit of hydrogen atom is 0.85 nm. Calculate the speed (in 10 m/sec) of electron
in this orbit.
AS0028
29. The velocity of e- in a certain Bohr orbit of the hydrogen atom bears the ratio 1:275 to the speed of light.
(i) What is the quantum no. "n" of the orbit.
(ii) Calculate the wave number (in 106 m–1) of the radiation emitted for the transition from the quatum
state (n+1) to the ground state.
AS0029
E 177
JEE (MAIN+ADVANCED)
NURTURE COURSE
Exercise
Atomic Structure
(English Medium)
, ALLEN
® Atomic Structure
EXERCISE # S-I
FUNDAMENTAL PARTICLES
æqö
1. The ratio of specific charges ç ÷ of an a-particle and a deuteron is x : 1.00. The value of 'x' is.
èmø
AS0001
2. Specific charges of two particles A and B are in ratio 2 : 3. If their mass ratio mA : mB is 2 : 3, then the
æ qA ö
ratio of their charges ç ÷ is 4.00 : x. The value of 'x' is.
è qB ø
AS0002
3. Arrange electron (e), proton (p) , neutron (n) and a-particles (a) , in the increasing order of their e/m
ratio.
®
AS0003
4. In oil drop experiment, the following charges were experimentally determined for five oil droplets
1.20 × 10–18 unit, 3.00 × 10–18 unit, 6.00 × 10–18 unit, 2.40 × 10–18 unit and 3.60 × 10–18 unit (unit
is arbitrary). What should be the charge on electron in this arbitrary unit (in the order of 10–19) ?
AS0004
5. The kinetic energy of a charged particle (charge = q) accelerated by a potential difference of 10000
volt is 1.6 × 10–15 Joule. The value of 'q' (in 10–19 coulomb) is.
AS0005
RUTHERFORD'S ATOMIC MODEL
6. If the radius of an atom is 2Å and the radius of its nucleus is 4 × 10–15 m. The ratio of volume of
nucleus to that of atom is x : 1015. The value of 'x' is.
AS0006
7. Radius of nucleus may be given as RN = R0.A1/3 , where A = mass number and R0 = constant.
Calculate the density (in 1017 kg m–3) of nucleus of an atom if R0 = 1.2 × 10–15.
[NA = 6 × 1023, 23 × 8p × (1.2)3 = 1000]
AS0007
node06\B0BC-BD\Kota\JEE(Advanced)\Nurture\Chem\Module\4-Ideal-Reas-Atomic-Chemical Eq\Eng\3. Atomic\02. Ex.p65
8. The ratio of distances of closest approach of a proton and an a-particle projected towards the same
nucleus with the same initial kinetic energy is x : 1. The value of 'x' is.
AS0008
9. An a-particle of K.E. 5.4 MeV is projected towards Cr-nucleus (Z = 24). What is its distance of
closest approach (in 10–14 m) ? (e = 1.6 × 10–19C)
AS0009
10. With what speed (in 107 ms–1) an a-particle should be projected towards stationary krypton nucleus
(Z = 36) such that it approaches upto 2.4 × 10–14m from the nucleus ?
(NA = 6 × 1023, e = 1.6 × 10–19C).
AS0010
E 175
,JEE-Chemistry ALLEN
®
WAVE CHARACTERISTICS
11. Calculate the wave length (in nm) of an electromagnetic radiation of frequency 2 × 1015 Hz.
AS0011
12. A radiostation emits the radiations of wavelength 2000 m (meter band of station). What is the frequency
band of that station, in kHz (Frequency of emitted radio waves) ?
AS0012
13. The wave numbers of two electromagnetic radiations are 4 × 106 m–1 and 2 × 105 cm–1. The ratio of
their frequencies is x : 1.00. the value of 'x' is.
AS0013
14. An electromagnetic radiation makes 5000 waves in 20 cm. The frequency of radiation (in 1012 Hz)
®
is.
AS0014
PLANCK'S QUANTUM THEORY
15. Calculate the energy (in 10–19 Joule) of a photon of wave length 4000 Å.
AS0015
16. The eyes of certain member of the reptile family pass a single visual signal to the brain when the
visual receptors are struck by photons of wavelength 662 nm . If a total energy of 3.0 ´ 10 -18 J is
required to trip the signal, what is the minimum number of photons that must strike the receptor.
(h = 6.62 × 10–34 J × s)
AS0016
17. Find the number of photons (in the order of 1022) of radiation of frequency 5 × 1013 s–1 that must be
absorbed in order to melt one gm ice when the latent heat of fusion of ice is 330 J/g.
(h = 6.6 × 10–34 J × sec.)
AS0017
18. A certain dye absorbs 4000 Å and fluoresces at 5000 Å these being wavelengths of maximum
absorption that under given conditions 40% of the absorbed energy is emitted. If the ratio of the
node06\B0BC-BD\Kota\JEE(Advanced)\Nurture\Chem\Module\4-Ideal-Reas-Atomic-Chemical Eq\Eng\3. Atomic\02. Ex.p65
number of quanta emitted to the number absorbed is x : 1.00, the value of 'x' is.
AS0018
19. The reaction between H2 and Br2 to form HBr in presence of light is initiated by the photo decomposition
of Br2 into free Br atoms (free radicals) by absorption of light. The bond dissociation energy of Br2 is
192 KJ/mole. What is the longest wavelength (in nm) of the photon that would initiate the reaction.
æ eV ö
ç1 = 96kJ / mol ; hc = 1240 ev ´ nm ÷
è atom ø
AS0019
20. The quantum yield for decomposition of HI is 0.2. In an experiment 0.01 moles of HI are decomposed.
Find the number of photons (in the order of 1022) absorbed. (NA = 6 × 1023)
AS0020
176 E
, ALLEN
® Atomic Structure
PHOTOELECTRIC EFFECT
21. The minimum energy required for the emission of a metal electron is 1.324 × 10–18 J. Calculate the
threshold wavelength (in nm) required to eject the electron ?
AS0021
22. A light source of wavelength l illuminates a metal and ejects photo electron with (KE)max = 1 eV.
l
Another light source of wave length , ejects photoelectrons from same metal with (KE)max=5eV.
3
Find the value of work function (eV) of metal.
AS0022
23. The dissociation energy of H2 is 482.5 KJ/mol. If H2 is exposed to radiant energy of wavelength
124 nm, what % of radiant energy will be converted into K.E.
ev
(1 = 96.5 kJ/mol, hc = 1240 eV × nm)
®
atom
AS0023
24. The K.E. of an electron emitted from tungstan surface is 3.06 eV. What voltage (in volt) would be
required to bring the electron to rest.
AS0024
25. Stopping potential [V volts] is plotted against frequency of light used [u].
Find work function (eV). (h = 6.62 × 10–34 J × s)
V(Volt)
1 3 5
(u × 10 ) Hertz
14
AS0025
BOHR’S MODEL
26. If the mass of electron is doubled, then find the new radius (in Å) of 1st orbit of H-atom ?
AS0026
node06\B0BC-BD\Kota\JEE(Advanced)\Nurture\Chem\Module\4-Ideal-Reas-Atomic-Chemical Eq\Eng\3. Atomic\02. Ex.p65
27. If an electron in H-atom jumps from one orbit to other its angular momentum doubles. If the new
radius is 'x' times the old radius, then find x ?
AS0027
28. 5
The radius of the an orbit of hydrogen atom is 0.85 nm. Calculate the speed (in 10 m/sec) of electron
in this orbit.
AS0028
29. The velocity of e- in a certain Bohr orbit of the hydrogen atom bears the ratio 1:275 to the speed of light.
(i) What is the quantum no. "n" of the orbit.
(ii) Calculate the wave number (in 106 m–1) of the radiation emitted for the transition from the quatum
state (n+1) to the ground state.
AS0029
E 177
