ECAT Pre Engineering Chemistry Chapter 5 MCQ Test With Answer

The wave number of the light emitted by a certain source is 2 x 10⁶m^-1. The wavelength of this light will be

• 500 nm A
• 500 m B
• 200 nm C
• 5 x 10⁷m D

• s A
• p B
• d C
• f D

The orbitals having n + l = 5 are

• 2p, 3d,3s A
• 3p, 3d, 5s B
• 3s, 4p, 4d C
• 5s, 4p, 3d D

The radius of second Bohr's orbit is

• 0.053 nm A
• 0.053/4 nm B
• 0.053 x 4 nm C
• 0.053 x 20 nm 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

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

The symbol of the element whose atoms have the outer most electronic configuration 2s²2p³is

• N A
• Li B
• P C
• Na 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

Splitting of spectral lines of the hydrogen atom under the influence or magnetic field is called

• Stark effect A
• Zeeman effect B
• Compton effect C
• Photoelectric effect D

No cathode rays are produced in the discharged tube when gas is under ordinary pressure even if voltage of 5000 to 10000 is applies. This reason is

• Voltage is low A
• Discharge tube is not coloured B
• Gas does not conduct current under ordinary pressure C
• Temperature low 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

Splitting of spectral lines when atoms are subjected to strong electron field is called

• Zeeman effect A
• Stark effect B
• Photoelectric effect C
• Compton effect D

The quantum number which determines the shape of the orbital is

• principal A
• azimuthal B
• magnetic C
• spin D

The e.m value for positive rays maximum for:

• Oxygen. A
• Nitrogen. B
• Helium. C
• Hydrogen. D

Their e/m, ratio resembles with that of electrons

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

Photons of yellow colour are ______ energetic than violet colour

• More A
• Less B
• Equal C
• None D

The value of R (Rydberg's constant) is _______ m-1

• 1.0974 x 107 A
• 1.0842 x 107 B
• 1.082 x 10-7 C
• Both a and b 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

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

The energy of the first electron is helium will be

• -13.6 eV A
• -54.4 eV B
• -5.44 eV C
• zero D

The radiations with wavelength shorter than violet light are called

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

In the ground state, an element has 13 electrons in its M shell. The element is

• Copper A
• Chromium B
• Nickel C
• Iron D

The wave number of light emitted by a certain source is 2 x 10⁵m. The wavelength of this light will be:

• 500 NM. A
• 500 M. B
• 200 NM. C
• 5 x 10⁷m 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

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

Which of the following is not a sub-atomic particle

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

Orbitals having same energy are called

• Hybrid orbitals A
• Valence orbitals B
• Degenerate orbitals C
• D-orbitals D

Pauli's principle is applicable to

• Degenerate orbits A
• Two electrons in the same orbital B
• One electron C
• None D

Balmer's series is in ______ region

• Visible A
• U V B
• I. R. C
• None D

Which of the following orbitals have a dumb bell shape?

• s A
• p B
• d C
• f D