ECAT Pre Engineering Chemistry Chapter 5 MCQ Test With Answer

The velocity of photon is:

• Independent of its wavelength. A
• Depends on its wavelength. B
• Equal to square of its amplitude C
• Depends on its source. D

Which have better penetrating power

• Alpha rays A
• Beta rays B
• Gamma rays C
• X-rays D

Energy of electron in an orbit according to Bohr theory is negative due to

• Repulsion of electrons in the same orb A
• At infinity energy is zero ad a traction towards nucleus decreases energy B
• Electron has negative charge C
• Product of positive nuclear charge and negative charge is negative D

If the radius of first Bohr orbit be a_o, then the radius of third Bohr orbit would be

• 3 x a_o A
• 6 x a_o B
• 9 x a_o C
• 1/2 x a_o D

• s A
• p B
• d C
• f D

Anode is the surface on which probability of finding electron is:

• 50% A
• Less than 10%. B
• More than 95%. C
• Zero. D

The nature of positive rays depend on:

• Nature of discharge tube. A
• Nature of resident gas. B
• Nature of electrode. C
• All of above. D

Which of the following is not a property of cathode rays

• They can produce x-rays when they strike a heavy metal anode A
• They can cause reduction reaction B
• They produce fluorescence in rare earth and minerals C
• They comprise neutral particles D

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

• 2n A
• 2n² B
• n² C
• n + 1 D

The rules which describe the distribution of electron in atomic energy levels are Auf-ban principle, Pauli's exclusion principle. Hunds rule. The pauli exclusion principle refers to the

• Orientation of orbital in space A
• Fact that two electrons in the same orbital should have opposite spins B
• Energy of the orbital C
• Spin of the electron D

Subsidiary quantum number specifies

• size of orbital A
• shape of orbital B
• orientations of orbitals C
• Nuclear stability D

1 erg of energy corresponds to

• 6.02 x 10²³J/mol A
• 6.02 x 10¹⁶J/mol B
• 1 erg/mol C
• 10^-7J/mol D

Quantum number value for 2p orbitals are:

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

The total values of magnetic quantum number of subshell are five, the subshell is

• S-subshell A
• P-subshell B
• D-subshell C
• F-subshell D

The quantum number which describes the shape of the orbital is

• Principle quantum number A
• Spin quantum number B
• Azimathal quantum number C
• Magnetic quantum number 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 number of spherical nodes in 3p orbitals are

• One A
• Three B
• Non C
• Two D

For principle quantum number n=4, the total number of orbitals having l = 3 is

• 3 A
• 7 B
• 5 C
• 9 D

Their e/m, ratio resembles with that of electrons

• Alpha rays A
• Beta rays B
• Gamma rays C
• X-rays D

Rutherford's experiment led to the discovery of

• Nucleus A
• Electron B
• Proton C
• alpha particle D

Which of the following particles has longest wavelength, if they have same speed:

• Proton. A
• Neutron. B
• Electron. C
• Positron. D

The electron in an atom

• moves randomly around the nucleus A
• has fixed space around the nucleus B
• is stationary in various energy levels C
• moves around its nucleus in definite energy levels D

Rutherford's atomic model suggests the existence of

• Atom A
• Nucleus B
• alpha particle C
• Measons D

The charge of an electron is determined by

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

Effective magnetic moment of Sc³⁺ion is

• 1.73 A
• 0 B
• 5.92 C
• 2.83 D

Consider the ground state of Cr atom (Z=24). The numbers of electrons with the azimuthal quantum numbers l = 1 and l = 2 are respectively

• 12 and 4 A
• 16 and 5 B
• 16 and 4 C
• 12 and 5 D

Charge on electron was discovered by:

• Millikan. A
• Crook. B
• Neil Bohr. C
• Rutherford. D

The energy of ionization of an atom is the energy difference between orbital

• 
  A
• 
  B
• 
  C
• 
  D

In which of the following pairs, the numbers of electrons in the outermost shell are different?

• As,Sb A
• Ge,Sn B
• In,pt C
• Se,Te D