The eyes of a reptile pass a visual signal to the brain when the visual receptors are struck by photons of wavelength 850 nm If an energy of 3 . 15 × 10 - 14 J is required to trip the signal, what is the minimum number of photons that must strike the receptor h = 6 . 6 × 10 - 34 ?

The energy of one photon is given by E = h c λ = 6 . 6 × 10 - 34 × 3 × 10 8 850 × 10 - 9 = 2 . 3 × 10 - 19 J The energy required to trip signal = 3 . 15 × 10 - 14 J n × E = E total photons that strike the receptor are The number of photons required is n = 3 . 15 × 10 - 14 2 . 3 × 10 - 19 = 1 . 37 × 10 5 photons

If the velocity of the electron in first orbit of H atom is 2 . 18 × 10 6 ms - 1 , what is its value in third orbit?

The velocity of an electron in n th orbit of H - atom is given by, v = 1 4 πε 0 2 πZe 2 nh On substituting the values of constants, 1 4 πε 0 = 9 × 10 9 Nm 2 C - 2 , h = 6 . 626 × 10 - 34 Js , e = 1 . 6 × 10 - 19 C We get the reduced formula, v = 2 . 18 × 10 6 × Z n Z = 1 , n = 3 v = 2 . 18 × 10 6 × 1 3 m / s v = 7 . 26 × 10 5 m / s

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The Vividh Bharati Station of All India Radio, Delhi broadcasts on a frequency of $1368 kHz$ (kiloHertz). Calculate the wavelength and wave number of the electromagnetic radiation emitted by the transmitter.

Important Questions on Structure of Atom

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Alpha Question Bank for Engineering: Chemistry>Chapter 2 - Structure of Atom>Exercise-1>Q 9

One quantum is absorbed per gaseous molecule of

{Br}_{2}

for converting into

Br

atoms. If light absorbed has wavelength

5000 Å

, calculate energy required in

kJ {mol}^{- 1}

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Alpha Question Bank for Engineering: Chemistry>Chapter 2 - Structure of Atom>Exercise-1>Q 10

The eyes of a reptile pass a visual signal to the brain when the visual receptors are struck by photons of wavelength

850 nm

If an energy of

3.15 \times 10^{- 14} J

is required to trip the signal, what is the minimum number of photons that must strike the receptor

(h = 6.6 \times 10^{- 34}) ?

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Alpha Question Bank for Engineering: Chemistry>Chapter 2 - Structure of Atom>Exercise-1>Q 12

If a light with frequency of

4.0 \times 10^{16}

Hz

emitted photoelectrons with double the kinetic energy as are emitted by the light of frequency

2.5 \times 10^{16} Hz

from the same metal surface then what is the threshold frequency of the metal?

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Alpha Question Bank for Engineering: Chemistry>Chapter 2 - Structure of Atom>Exercise-1>Q 13

Which state of the triply ionised beryllium,

{Be}^{3 +}

, has the same radius as that of the ground state of hydrogen atom?

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Alpha Question Bank for Engineering: Chemistry>Chapter 2 - Structure of Atom>Exercise-1>Q 14

If the velocity of the electron in first orbit of

H

atom is

2.18 \times 10^{6} {ms}^{- 1},

what is its value in third orbit?

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Alpha Question Bank for Engineering: Chemistry>Chapter 2 - Structure of Atom>Exercise-1>Q 15

Consider Bohr's theory for hydrogen atom. The magnitude of angular momentum, orbit radius and velocity of the electron in

n^{th}

energy state in a hydrogen atom are

l, r

and

v

respectively. Find out the value of

{}^{'}x^{'},

if product of

v, r

and

l (vrl)

is directly proportional to

n^{x} .

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Alpha Question Bank for Engineering: Chemistry>Chapter 2 - Structure of Atom>Exercise-1>Q 16

Find the ratio of the time period of

2^{nd}

Bohr orbit of

{He}^{+}

and

4^{th}

Bohr orbit of

{Li}^{2 +} .

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Alpha Question Bank for Engineering: Chemistry>Chapter 2 - Structure of Atom>Exercise-1>Q 18

A hydrogen sample is prepared in a particular excited state. Photons of energy $2.55 eV$ get absorbed into the sample to take some of the electrons to a further excited state $B .$ Find orbit numbers of the states $A$ and $B .$ Given the allowed energies of hydrogen atom:

$E_{1} = - 13.6 eV, E_{2} = - 3.4 eV, E_{3} = - 1.5 eV, E_{4} = - 0.85 eV, E_{5} = - 0.54 eV$

The Vividh Bharati Station of All India Radio, Delhi broadcasts on a frequency of 1368 kHz (kiloHertz). Calculate the wavelength and wave number of the electromagnetic radiation emitted by the transmitter.

Important Questions on Structure of Atom

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The Vividh Bharati Station of All India Radio, Delhi broadcasts on a frequency of $1368 kHz$ (kiloHertz). Calculate the wavelength and wave number of the electromagnetic radiation emitted by the transmitter.