Electrons are emitted with zero velocity from a metal surface when it is exposed to radiation of wavelength 6800 A ° . Calculate threshold frequency ν 0 and work function W 0 of the metal.

Given: Threshold wavelength of radiation λ 0 = 6800 Å = 6800 × 10 - 10 m = 6 .8 × 10 - 7 m Formula: Threshold frequency ν 0 of the metal = c λ 0 = 3 × 10 8 ms - 1 6 .8 × 10 - 7 m = 4 .41 × 10 14 s - 1 Thus, the work function W 0 of the metal = hv 0 = 6 .62 × 10 - 34 Js 4 .41 × 10 14 s - 1 = 2 .919 × 10 - 19 J

Electrons are emitted with zero velocity from a metal surface when it is exposed to radiation of wavelength 6800 A ° . Calculate threshold frequency ν 0 and work function W 0 of the metal.

Given: Threshold wavelength of radiation λ 0 = 6800 Å = 6800 × 10 - 10 m = 6 .8 × 10 - 7 m Formula: Threshold frequency ν 0 of the metal = c λ 0 = 3 × 10 8 ms - 1 6 .8 × 10 - 7 m = 4 .41 × 10 14 s - 1 Thus, the work function W 0 of the metal = hv 0 = 6 .62 × 10 - 34 Js 4 .41 × 10 14 s - 1 = 2 .919 × 10 - 19 J

The energy associated with the first orbit in the hydrogen atom is – 2 . 18 × 10 - 18 J atom - 1 . What is the energy associated with the fifth orbit ?

E n = - 13 .6 Z 2 n 2 eV Given: hydrogen orbit ( n ) = 5 For hydrogen, atomic number ( Z ) = 1 E 5 = - 13 .6 5 2 eV = - 13 .6 25 eV = - 0 . 544 eV ( ∴ 1 eV = 1 .6 × 10 - 19 J ) = - 0 . 544 eV × 1 .6 × 10 - 19 J = - 8 .704 × 10 - 20 J

E M B I B E

Textbook for Class XI Chemistry Part I>Chapter 2 - Structure of Atom>EXERCISES>Q 2.12

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11th CBSE

IMPORTANT

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Electrons are emitted with zero velocity from a metal surface when it is exposed to radiation of wavelength $6800 \overset{°}{A}$ . Calculate threshold frequency $(ν_{0})$ and work function $(W_{0})$ of the metal.

Important Questions on Structure of Atom

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IMPORTANT

Textbook for Class XI Chemistry Part I>Chapter 2 - Structure of Atom>EXERCISES>Q 2.13

What is the wavelength of light emitted when the electron in a hydrogen atom undergoes transition from an energy level with

n = 4

to an energy level with

n = 2

?

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11th CBSE

IMPORTANT

Textbook for Class XI Chemistry Part I>Chapter 2 - Structure of Atom>EXERCISES>Q 2.14

How much amount of energy is required to ionise a

H

atom if the electron occupies

n = 5

orbit? Compare your answer with the ionization enthalpy of

H

atom (energy required to remove the electron from

n = 1

orbit).

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IMPORTANT

Textbook for Class XI Chemistry Part I>Chapter 2 - Structure of Atom>EXERCISES>Q 2.15

What is the maximum number of emission lines when the excited electron of a

H

atom in

n = 6

drops to the ground state?

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11th CBSE

IMPORTANT

Textbook for Class XI Chemistry Part I>Chapter 2 - Structure of Atom>EXERCISES>Q 2.16

The energy associated with the first orbit in the hydrogen atom is

- 2.18 \times 10^{- 18} J {atom}^{- 1}

. What is the energy associated with the fifth orbit ?

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IMPORTANT

Textbook for Class XI Chemistry Part I>Chapter 2 - Structure of Atom>EXERCISES>Q 2.16

Calculate the radius of Bohr’s fifth orbit for hydrogen atom.

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11th CBSE

IMPORTANT

Textbook for Class XI Chemistry Part I>Chapter 2 - Structure of Atom>EXERCISES>Q 2.17

Calculate the wavenumber for the longest wavelength transition in the Balmer series of atomic hydrogen.

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11th CBSE

IMPORTANT

Textbook for Class XI Chemistry Part I>Chapter 2 - Structure of Atom>EXERCISES>Q 2.18

What is the energy in joules, required to shift the electron of the hydrogen atom 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