Chemistry Most Important 20 Mcqs

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(1) cathode rays emitted from cathode are.

(a) canal rays

(b) protons

(c) electrons

(d) positrons

 

(2) charge to mass ratio (e/m) of the electron is determined by.

(a) R.A. Millikan

(b) J.J. Thomson

(c) G.J Stoney

(d) None of these

 

(3) Neutron was discovered by.

(a) Mosely

(b) Millikan

 (c) Chadwick

(d) Rutherford

 

(4) Which radiations are of very high frequency.

(a) IR

(b) UV

(c) Visible

 (d) x-rays

 

(5) Rutherford bombarded thin gold foil with.

(a) beta particles

(b) neutron

 (c) alpha particles

(d) electron

 

(6) The nucleus is surrounded by a number of electrons equal to the number of.

(a) neutron

 (b) proton

(c) negatron

(d) positron

 

(7) According to Rutherford’s model, the nucleus is surrounded by.

(a) proton

(b) neutron

(c) positron

 (d) electron

 

(8) Nucleus was discovered by.

(a) Schroeder

(b) Chadwick

(c) Bohr

 (d) Rutherford

 

(9) The range of visible spectrum is.

(a) 300-600nm

(b) 600-900nm

 (c) 400-750nm

(d) 100-300nm

 

(10) The wavelength of red light is.

 (a) 750 nm

(b) 600 nm

(c) 500nm

(d) 400nm

 

(11) The spectrum of incandescent gas is.

(a) absorption

(b) emission

 (c) line

(d) continuous

 

(12) The wave number is inverse of.

(a) time period

(b) intensity

(c) frequency

 (d) wavelength

 

(13) An instrument that measures the intensity and frequency of emitted or absorbed radiation is called.

(a) voltmeter

(b) polarimeter

 (c) spectrometer

(d) prism

 

(14) The number of waves passing through a point in one second is called.

(a) wave number

(b) velocity

 (c) frequency

(d) wavelength

 

(15) The distance between two successive crests or troughs is called.

(a) velocity

(b) frequency

 (c) wavelength

(d) intensity

 

(16) When a substance that has absorbed energy emits it in the form of radiation, the spectrum is.

(a) absorption spectrum

 (b) emission spectrum

(c) line spectrum

(d) continuous spectrum

 

(17) When the electron jumps from third, fourth, fifth orbits to the second orbit, the transitions are known as.

(a) paschen

(b) pfund

 (c) balmer

(d) brackett

 

(18) When the electron jumps from second, third, fourth orbit to the first orbit, the transitions are known as.

(a) balmer series

 (b) layman series

(c) pfund series

(d) brackett series

 

(19) paschen, pfund and brackett series are found in.

(a) UV region

(b) visible region

 (c) IR region

(d) none of these

 

(20) Bohrs theory satisfactorily explains.

(a) stability of atom

(b) ionization energy

(c) spectra of hydrogen

 (d) all of the above

(1) cathode rays emitted from cathode are.

(a) canal rays

(b) protons

(c) electrons

(d) positrons

 

(2) charge to mass ratio (e/m) of the electron is determined by.

(a) R.A. Millikan

(b) J.J. Thomson

(c) G.J Stoney

(d) None of these

 

(3) Neutron was discovered by.

(a) Mosely

(b) Millikan

 (c) Chadwick

(d) Rutherford

 

(4) Which radiations are of very high frequency.

(a) IR

(b) UV

(c) Visible

 (d) x-rays

 

(5) Rutherford bombarded thin gold foil with.

(a) beta particles

(b) neutron

 (c) alpha particles

(d) electron

 

(6) The nucleus is surrounded by a number of electrons equal to the number of.

(a) neutron

 (b) proton

(c) negatron

(d) positron

 

(7) According to Rutherford’s model, the nucleus is surrounded by.

(a) proton

(b) neutron

(c) positron

 (d) electron

 

(8) Nucleus was discovered by.

(a) Schroeder

(b) Chadwick

(c) Bohr

 (d) Rutherford

 

(9) The range of visible spectrum is.

(a) 300-600nm

(b) 600-900nm

 (c) 400-750nm

(d) 100-300nm

 

(10) The wavelength of red light is.

 (a) 750 nm

(b) 600 nm

(c) 500nm

(d) 400nm

 

(11) The spectrum of incandescent gas is.

(a) absorption

(b) emission

 (c) line

(d) continuous

 

(12) The wave number is inverse of.

(a) time period

(b) intensity

(c) frequency

 (d) wavelength

 

(13) An instrument that measures the intensity and frequency of emitted or absorbed radiation is called.

(a) voltmeter

(b) polarimeter

 (c) spectrometer

(d) prism

 

(14) The number of waves passing through a point in one second is called.

(a) wave number

(b) velocity

 (c) frequency

(d) wavelength

 

(15) The distance between two successive crests or troughs is called.

(a) velocity

(b) frequency

 (c) wavelength

(d) intensity

 

(16) When a substance that has absorbed energy emits it in the form of radiation, the spectrum is.

(a) absorption spectrum

 (b) emission spectrum

(c) line spectrum

(d) continuous spectrum

 

(17) When the electron jumps from third, fourth, fifth orbits to the second orbit, the transitions are known as.

(a) paschen

(b) pfund

 (c) balmer

(d) brackett

 

(18) When the electron jumps from second, third, fourth orbit to the first orbit, the transitions are known as.

(a) balmer series

 (b) layman series

(c) pfund series

(d) brackett series

 

(19) paschen, pfund and brackett series are found in.

(a) UV region

(b) visible region

 (c) IR region

(d) none of these

 

(20) Bohrs theory satisfactorily explains.

(a) stability of atom

(b) ionization energy

(c) spectra of hydrogen

 (d) all of the above

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