ECAT Pre Engineering Chemistry Chapter 5 MCQ Test With Answer

The value of charge on electron is

• 1.602 x 10^-19coulombs A
• 1.602 x 10^-18coulombs B
• 1.602 x 10^-17coulombs C
• 1.602 x 10^-16 coulombs D

Which quantum number is sufficient to describe the electron is hydrogen atom?

• l A
• n B
• m C
• s D

The quantum number which describe the orientation of the orbitals is

• Spin quantum number A
• Principle quantum number B
• Azimathal quantum number C
• Magnetic quantum number D

Which of the following is not a sub-atomic particle

• Electron A
• Proton B
• Neutron C
• Deuteron D

Which one of the following statements is true about discovery of neutrons?

• These particles were formed by the bombardment of Alpha-particles on Beryllium. A
• These particles are formed by the spiting of alpha-particles. B
• These particles were discovered by natural radioactivity. C
• None of above. D

Alpha rays consist of:

• Neutrons. A
• Helium nucleus. B
• Protons. C
• Hydrogen nucleus. D

With increasing principle quantum number, the energy difference between adjacent energy levels in H atom

• Decreases A
• Increases B
• Remains constant C
• Decreases for low value of Z and increase for higher value of Z D

• Plank's equations A
• de Broglie's equations B
• Heisenburg's equation C
• None D

Heaviest particle is

• Meson A
• Neutron B
• Proton C
• Electron D

The orbital in Rutherford's model is

• Spiral A
• Circular B
• Both C
• None D

The order of frequency of the following radiations unltraviolet, visible, infrared and microwave is

• Microwave > infrared > visible > ultraviolet A
• Visible > ultraviolet > microwave > infrared B
• Ultraviolet > visible > infrared > microwave C
• Infrared > microwave > ultraviolet > visible D

For a 3P subshell the set of principle and azimuthal quantum number is

• n = 1 , l = 2 A
• n = 3, l = 0 B
• n = 3, l = 1 C
• n = 1, l = 3 D

The nature of positive ray depend on:

• The nature of electrode. A
• The nature of discharge tube. B
• The nature of residual gas. C
• All of above. D

Which of the following is not charged particle

• Proton A
• Electron B
• Neutron C
• Hydrogen nucleus D

The principle quantum number describes

• The distance form the nucleus A
• The shape of the orbital B
• The orientation of the orbital C
• The spin of the electron D

When the electron jumps form third, fourth, fifth orbits to the second orbit, the transitions are known as

• Paschen A
• Pfund B
• Balmer C
• Brackett D

In Bohr model of hydrogen atom the distance between adjacent orbits increases away from the nucleus, the energy difference between the orbits

• Increases A
• Decreases B
• Reaming same C
• Orbits coincide D

The total number of orbitals in a shell with principal quantum number 'n' is

• 2n A
• 2n² B
• n² C
• n + 1 D

Electrons in degenerate orbitals are placed in separate orbitals with same spin according to

• Hund's rule A
• Pauli exclusion principle B
• Aufbau principle C
• Mosley's law D

With the reference of w/m ratio of anode rays, the e/m ratio of cathode rays s:

• Greater. A
• same. B
• Smaller. C
• Not fixed. D

Charge to mass ratio (e/m) of the electron is determined by

• R. A. Millikan A
• J. J. Thompson B
• G. J, Stoney C
• None of these D

The radiations with wavelength shorter than violet light are called

• Ultraviolet A
• Infrared B
• Microwave C
• Radio frequency D

An electron with n = 3 , l = 2 will be in the sub-shell

• 3p A
• 3d B
• 3f C
• 3s D

When electron jumps from n₂= 2,3,4,5,.... orbit to n₁= 1 orbit in the hydrogen atom, the radiations emitted give the spectral lines

• Lyman series A
• Blamer series B
• Paschen series C
• Brackett series D

Sodium chloride imparts a yellow colour to the Bunsen flame. This can be interpreted due to the

• low ionization energy of sodium A
• sublimation of metallic sodium to give yellow vapour B
• emission of excess energy absorbed as a radiation in the visible region as a radiation in the visible region C
• photosenitivity D

e/m of cathode rays is same but for positive rays e/m changes by changing gas in the discharge tube because

• Cathode rays are small sized particles A
• Cathode rays have same charge B
• Nature of cathode rays same for all gasses, but masses of nuclei are different for different gases C
• Temperature of cathode rays higher D

The total number of possible values of magnetic quantum number for the value of l=3 is

• 3 A
• 1 B
• 5 C
• 7 D

The charge of an electron is determined by

• J.J. Thomson A
• Crooks B
• Perrin C
• R.A.Millikan D

If the value of principal quantum number is 3. the total possible values for magnetic quantum number will be

• 1 A
• 4 B
• 9 C
• 12 D

Light emitted from a source has its wave length 500nm, then its wave number will be

• 2 x 10⁶m^-1 A
• 2 x 10⁷m^-1 B
• 5 x 10⁸ m^-1 C
• 5 x 10⁹m^-1 D