Free NEET Chemistry multiple-choice questions on Dual Nature & Uncertainty. Attempt each question and reveal the answer with a full explanation.
The wavelength associated with a ball of mass 0.1 kg moving with a velocity of 10 m/s is: ( h = 6.6 10 -34 J s ) 6.6 10 -34 m 6.6 10 -33 m 6.6 10 -35 m 1.1 10 -32 m The value of Planck's constant is 6.63 10 -34 J s . The speed of light is 3 10 17 nm s -1 . Which value is closest to the wavelength in nanometers of a quantum of light with frequency 6 10 15 s -1 ? 50 25 75 10 Calculate the energy in joule corresponding to light of wavelength 45 , nm : (Planck's constant h = 6.63 10 -34 , Js ; speed of light c = 3 10 8 , ms -1 ) 6.67 10 15 6.67 10 11 4.42 10 -15 4.42 10 -18 If the velocity of an electron in Bohr's first orbit is 2.19 10 6 m/s , calculate the de Broglie wavelength associated with it. ( m e = 9.1 10 -31 kg ) 3.32 10 -10 m 3.32 10 -12 m 9.1 10 -34 m 6.6 10 -10 m Which of the following is the energy of a photon of light with a wavelength of 6000 Å ? 3.31 10 -19 J 3.31 10 -12 J 3.31 10 -22 J 1.6 10 -19 J The de Broglie wavelength of an electron moving with a kinetic energy E is . If the kinetic energy is increased to 4E , the new wavelength will be: 2 2 4 4 If the kinetic energy of a particle is doubled, its de Broglie wavelength becomes: 1/ h h 2 times 2 times 4 times 1/2 times If the position of an electron is known with zero uncertainty ( h x = 0 ), the uncertainty in its momentum ( h p ) is: Infinite Zero h/4 h 1 Calculate the ratio of de Broglie wavelengths of a proton and an h -particle if they are moving with the same velocity. 4:1 1:4 2:1 1:2 The mass of a photon of wavelength is given by: h c h c hc c h If the wavelength of a particle is 10 -10 m and its mass is 10 -30 kg , what is its velocity ( h = 6.6 10 -34 J s )? 6.6 10 6 m/s 6.6 10 -6 m/s 1.5 10 7 m/s 6.6 10 5 m/s The experimental evidence for the wave nature of electrons was first provided by: Davisson and Germer Rutherford J.J. Thomson Max Planck If the kinetic energy of an electron is increased four times, the de Broglie wavelength of the electron will become: Half of the original value Double of the original value Four times the original value One-fourth of the original value An electron is accelerated from rest through a potential difference of V volts. Its de Broglie wavelength is given by: = 12.27 V Å = 0.101 V Å = 1227 V Å = 1.227 V Å An electron is accelerated from rest through a potential difference of 100 V . Its de Broglie wavelength is approximately: 1.23 Å 12.27 Å 0.123 Å 122.7 Å If the uncertainty in the position of an electron is 1.0 , , what is the minimum uncertainty in its momentum? ( h = 6.626 10 -34 J s ) 5.27 10 -25 kg m/s 5.27 10 -24 kg m/s 1.05 10 -24 kg m/s 6.63 10 -25 kg m/s The de Broglie wavelength of a neutron of energy E is . If its kinetic energy is increased to 9E , its new de Broglie wavelength will be: /3 3 /9 9 According to the Heisenberg Uncertainty Principle, if the uncertainty in the momentum of a particle is doubled, the minimum uncertainty in its position will become: Half Double Four times Unchanged The work function of Caesium is 2.14 eV . When light of frequency 6 10 14 Hz is incident on the metal surface, photoemission of electrons occurs. What is the maximum kinetic energy of the emitted photoelectrons? ( h = 6.63 10 -34 J s ) 0.34 eV 0.48 eV 2.48 eV 0.28 eV The uncertainty in momentum of an electron is 1 10 -5 kg m s -1 . The uncertainty in its position will be ( h = 6.626 10 -34 J s ): 5.27 10 -30 m 1.05 10 -26 m 5.27 10 -28 m 2.5 10 -25 m Given: The mass of electron is 9.11 10 -31 Kg Planck constant is 6.626 10 -34 Js, the uncertainty involved in the measurement of velocity within a distance of 0.1Å is:- 5.79 10 6 ms -1 5.79 10 7 ms -1 5.79 10 8 ms -1 5.79 10 5 ms -1 If uncertainty in position and momentum are equal, then uncertainty in velocity is: 1 2m h h h 4 m 1 m h The wave mechanical model of the atom is based on: Both de Broglie's equation and Heisenberg's uncertainty principle Only de Broglie's equation Only Heisenberg's uncertainty principle Bohr's theory of quantization In the photoelectric effect, if the frequency of incident radiation is doubled (above threshold), the maximum kinetic energy of the photoelectrons will: Increase by more than double Become exactly double Become half Remain unchanged An electron is moving with a velocity of 2.5 10 6 m/s . If the uncertainty in its velocity is 0.1 % , the uncertainty in its position ( m e = 9.1 10 -31 kg ) is approximately: 2.3 10 -8 m 2.3 10 -10 m 5.1 10 -8 m 1.1 10 -9 m A particle having a mass of 1 mg has a velocity of 450 m/s . The uncertainty in velocity is 0.01 % . The uncertainty in its position is ( h = 6.63 10 -34 J s ): 1.17 10 -28 m 1.17 10 -31 m 1.17 10 -34 m 5.27 10 -30 m The uncertainty in position of an electron ( m = 9.1 10 -31 kg ) moving with a velocity of 300 m/s accurate up to 0.001 % is ( h = 6.63 10 -34 J s ): 1.93 10 -2 m 1.93 10 -4 m 5.79 10 -2 m 3.86 10 -3 m If the uncertainty in the velocity of a particle of mass 1 g is 5.27 10 -21 m s -1 , the uncertainty in its position is: ( h = 6.626 10 -34 J s ) 10 -11 m 10 -8 m 10 -14 m 10 -10 m Which of the following is the correct representation of the Heisenberg Uncertainty Principle? x p h 4 x v h 4 x p = h 2 E t < h 4 Which of the following graphs correctly represents the relation between the de Broglie wavelength ( ) and the momentum ( p ) of a particle? A rectangular hyperbola ( λ 1/p ) A straight line passing through origin ( λ p ) A parabola ( λ p 2 ) A horizontal straight line The dual nature of matter was proposed by de Broglie. Which experiment experimentally verified the wave nature of electrons? Davisson and Germer Experiment Mulliken's Oil Drop Experiment Rutherford Gold Foil Experiment Stark Effect Experiment The experimental evidence that electrons have wave-like properties was provided by the observation of: Electron diffraction by a crystal lattice The photoelectric effect The discrete lines in atomic spectra The deflection of cathode rays in a magnetic field Davisson and Germer experiment provided the first experimental evidence for: Wave nature of electrons Particle nature of light Quantization of energy Existence of the nucleus A particular station of All India Radio, New Delhi, broadcasts on a frequency of 1,368 kHz . The wavelength of the electromagnetic radiation emitted by the transmitter is: (Given c = 3.0 10 8 m s -1 ) 219.3 m 219.3 km 21.92 m 2193 m