When a certain metal was irradiated with a light of frequency $3.2 \times 10^{16} Hz$ , the photoelectrons had twice the kinetic energy as emitted when the same metal was irradiated with light of frequency $2.0 \times 10^{16} Hz$ . Calculate the threshold frequency $(v_{0})$ of the metal.

Important Questions on Structure of Atom

HARD

11th ICSE

IMPORTANT

ALL IN ONE ISC Chemistry CLASS 11>Chapter 2 - Structure of Atom>Chapter Practice>Q 21

What is the energy in joules required to excite the electron of the hydrogen from the first Bohr orbit to the fifth Bohr orbit and what is the wavelength of the light emitted when the electron returns to the ground state? The ground state electron energy is

- 2.18 \times 10^{- 11}

ergs.

HARD

11th ICSE

IMPORTANT

ALL IN ONE ISC Chemistry CLASS 11>Chapter 2 - Structure of Atom>Chapter Practice>Q 22

The effect of uncertainty principle is significant only for motion of microscopic particles and is negligible for the macroscopic particle. Justify the statement with the help of a suitable example.

MEDIUM

11th ICSE

IMPORTANT

ALL IN ONE ISC Chemistry CLASS 11>Chapter 2 - Structure of Atom>Chapter Practice>Q 22

Calculate the velocity condition for the wavelength associated with a moving electron to be equal to the wavelength associated with a moving proton. (Mass of electron

= 9.11 \times 10^{- 28} g

; Mass of proton

= 1.67 \times 10^{- 24} g

;

h = 6.6 \times 10^{- 34} Js; J \equiv {kgm}^{2} s^{- 2}

)

HARD

11th ICSE

IMPORTANT

ALL IN ONE ISC Chemistry CLASS 11>Chapter 2 - Structure of Atom>Chapter Practice>Q 23

Why is

+ 2

oxidation state of

Mn (25)

quite stable, while the same is not true for iron

(26)

?

HARD

11th ICSE

IMPORTANT

ALL IN ONE ISC Chemistry CLASS 11>Chapter 2 - Structure of Atom>Chapter Practice>Q 23

What is meant by dual nature of electrons? Calculate the energy and wavelength of the photon emitted by hydrogen atom when electron makes a transition from