ECAT Pre Engineering Chemistry Chapter 5 MCQ Test With Answer

The radiations with wavelength shorter than violet light are called

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

In the ground state of an atom, the electron is present

• In the nucleus A
• In the second shell B
• Nearest to the nucleus C
• Farthest from the nucleus D

Bohr model of atom is contradicted by:

• Planck's quantum theory A
• Pauli's exclusion theory B
• Heisenberg's uncertainty principle. C
• All of above. D

The ratio of the ionization energy of H and Be³⁺is

• 1 : 1 A
• 1 : 3 B
• 1 : 9 C
• 1 : 16 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 valence orbital configuration of an element with atomic number 23 is

• 3d⁵ A
• 3d³, 4s² B
• 3d³, 4s¹, 4p¹ C
• 3d²,4s²,4p¹ 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

Orbital having same energy is called:

• Hybrid orbital. A
• Valence orbital. B
• Degenerate orbital. C
• D-orbital. D

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

• l A
• n B
• m C
• s D

Proton was discovered by:

• Chadwick A
• J.J. Rhomson B
• Millikan. C
• Goldstein. D

The correct set of quantum numbers (n,l and m) respectively of the unpaired electron of chlorine atom is

• 2,1,0 A
• 2,1,1 B
• 3,1,1 C
• 3,2,1 D

Balmer's series is in ______ region

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

The spectrum of He is expected to be similar to that of

• H A
• Na B
• He⁺ C
• Li⁺ D

In the atomic emission spectrum the lines which appear bright, appear dark in absorption spectrum because

• The radiations emitted in emission spectrum are absorbed in absorption spectrum A
• Atomic emission spectrum is continuous B
• Atomic absorption spectrum is continuous C
• Distance between the lines increases D

The wave length of electron as wave is 0.5 nm. What is the wave length in meter

• 5 x 10^-9 A
• 5 x 10^-12 B
• 5 x 10^-6 C
• 5 x 10^-10 D

n + l value for 4f will

• 2 A
• 5 B
• 7 C
• 9 D

The range of visible spectrum is

• 300 - 600 nm A
• 600 - 900 nm B
• 400 - 750 nm C
• 100 - 300 nm D

E = hv is the

• Spectral equation A
• Plank's equation B
• de Broglie's equation C
• None of these D

The quantum number which determines the shape of the orbital is

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

When electrons revolve in stationary orbits

• There is no change in energy level A
• They vecome stationary B
• They are gaining kinetic energy C
• There is increase in energy D

In the ground state of an atom the electron is present

• In the nucleus A
• In the second shell B
• Nearest to the nucleus C
• Farthest from the nucleus 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 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

Maximum potential energy that an electron can have within the atom is:

• Equal to zero. A
• Less than zero. B
• Greater than zero. C
• Infinite D

The e.m value for positive rays maximum for:

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

When potassium metal is exposed to violet light

• Ejection of electrons takes place A
• Ejection of some potassium atoms occurs B
• There is no effect C
• The absorption of electrons takes place D

In Millikan method the oil droplet falls under the force of gravity but it moves upward due to

• Electric field A
• Magnetic field B
• Incident light C
• X-rays D

• s A
• p B
• d C
• f 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

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