De Broglie's Hypothesis

Q.

The stopping potential for electrons emitted from a photosensitive surface illuminated by the light of wavelength $491nm$ is $0.710V$. When the incident wavelength is changed to a new value, the stopping potential is $1.43V$. What is this new wavelength?

1. $400nm$

2. $382nm$

3. $309nm$

4. $329nm$

Q. A 0.66 kg ball is moving with a speed of 100 m/s. The associated wavelength will be $(h=6.6\times {10}^{-34}Js)$

1. 
2. 
3. 
4. 

Q. The de-Broglie wavelength associated with a ball of mass 1kg having kinetic energy 0.5 J is

1. 
2. 
3. 
4. 

Q. The de-Broglie wavelength ($\lambda$) associated with a photoelectron varies with the frequency ($v$) of the incident radiation as, [$v_0$ is threshold frequency]

Q.

The de-Broglie wavelength associated with a material particle is

1. Directly proportional to its energy

2. Directly proportional to momentum

3. Inversely proportional to its energy

4. Inversely proportional to momentum

Q. The de Broglie wavelength of electron of He+ ion is 3.329 A. If the photon emitted upon de-excitation of this He+ ion is made to hit H-atom in its ground state so as to librate electron from it, what will be the de-Broglies wavelength of photoelectron?

Q. Number of spectral lines falling in Balmer series whenelectrons are de-excited from nth shell will be givenas(1) (n- 2) in UV(2) (n- 2) in visible region(3) (n-3) in near IR(4) (n-3) in far IR

Q.

Calculate the value of azimuthal quantum number for the subshell notation 4d?

1. 4

2. 3

3. 2

4. 1

Q.

If the radius of first orbit of H - atom is $a_0$, then de Broglie wavelength of electron in 4th orbit is ?

1. $2\pi a_0$

2. $16a_0$

3. $\frac{a_0}{4}$

4. $8\pi a_0$

Q.

Indicate the correct statement for a 1-L sample of $N_2$(g) and $C{O}_2$(g) at 298 K and 1 atm pressure

1. The average translational KE per molecule is the same in and

2. The rms speed remains constant for both and

3. The density of is less than that of

4. The total translational KE of both and is the same

Q. The de Broglie wavelength of a sand grain weighing 2 mg blown by a wind of 10 m/s is:

1. $3.31\times {10}^{-29}m$
2. $1.12\times {10}^{-29}m$
3. $2.21\times {10}^{-29}m$
4. $4.42\times {10}^{-29}m$

Q.

In which of the following situations, the heavier of the two particles has smaller de Broglie wavelength? The two particles

1. Move with the same speed

2. Move with the same kinetic energy

3. Have fallen through the same height

4. Move with the same linear momentum

Q. The approximate wavelength associated with a gold ball weighing 200 gm and moving at a speed of 5 m/h is in the order of ?

1. ${10}^{-1}m$
2. ${10}^{-20}m$
3. ${10}^{-30}m$
4. ${10}^{-40}m$

Q. The de Broglie wavelength of a tennis ball of mass 30 g moving with a velocity of $\text{20}m/s$ is approximately: $\text{(Planck's constant,}h=6.63\times {10}^{-34}Js)$

1. ${10}^{-31}m$
2. ${10}^{-16}m$
3. ${10}^{-25}m$
4. ${10}^{-33}m$

Q. Calculate the wavelength of electron in an orbit of $B{e}^{3+}$ ion having radius equal to the Bohr's radius ($a_0$). Also report the accelerating potential that must be imparted to an electron originally at rest to give an effective wavelength as calculated above.

1. $9.66\times {10}^{-10}m$ and 27.2 eV
2. $7.66\times {10}^{-12}m$ and 54.4 eV
3. $1.66\times {10}^{-10}m$ and 54.4 eV
4. Cannot be calculated

Q. Find the de Broglie wavelength (in m) of an electron moving in the first Bohr orbit of hydrogen.

1. $3.34\times {10}^{-10}$
2. $8.34\times {10}^{-9}$
3. $5.34\times {10}^{-10}$
4. $6.34\times {10}^{-9}$

Q. 57.If the de-Broglie wavelength of an electron revolving in 2nd orbit of H atom is X then radius of that orbit is given by. OPTIONS:A)X/pi B)2X/pi C)X/2pi D)Cannot be predicted

Q.

The time taken by the electron in one complete revolution in the $n^{th}$ Bohr's orbit of the hydrogen atom is:

1. Inversely proportional to n²

2. Directly proportional to n³

3. Directly proportional to h/2π

4. Inversely proportional to n/h

Q. what is meant by angular momentum of s electron is zero

Q. De-Broglie wavelength of an electron travelling with speed equal to 1% of the speed of light:

1. 400 pm
2. 120 pm
3. 242 pm
4. 375 pm

Q. If the kinetic energy of an electron is increased to 16 times the initial value, how many times would the new de Broglie wavelength be?

1. 4
2. 0.25
3. 16
4. 0.5

Q. A proton is accelerated through a potential difference of $V$ volts. The de Broglie's wavelength associated with it is:

1. $\sqrt{\frac{150}{V}}\stackrel{\circ }{A}$
2. $\frac{0.287}{\sqrt{V}}\stackrel{\circ }{A}$
3. $\frac{0.202}{\sqrt{V}}\stackrel{\circ }{A}$
4. $\frac{0.101}{\sqrt{V}}\stackrel{\circ }{A}$

Q. Find the de Broglie wavelength (in m) of an electron moving in the first Bohr orbit of hydrogen.

1. $3.34\times {10}^{-10}$
2. $8.34\times {10}^{-9}$
3. $5.34\times {10}^{-10}$
4. $6.34\times {10}^{-9}$

Q. The de Broglie wavelength of a tennis ball of mass 60 g moving with a velocity of $\text{10}m/s$ is approxiamately: $\text{(plancks's constant,}h=6.63\times {10}^{-34}Js)$

1. ${10}^{-31}m$
2. ${10}^{-16}m$
3. ${10}^{-25}m$
4. ${10}^{-33}m$

Q. The de broglie wavelength of an electron (initially at rest) accelerated by an electric potential 'V' volts is given by:
Given: $m_e=9.1\times {10}^{-31}kg,e=1.6\times {10}^{-19}C,$
$h=6.6\times {10}^{-34}Js$

1. $\lambda =\frac{2.46}{V}nm$
2. $\lambda =\frac{1.23}{V}nm$
3. $\lambda =\frac{1.23}{\sqrt{V}}nm$
4. $\lambda =\frac{2.46}{\sqrt{V}}nm$

Q. Calculate the wavelength associated with an electron moving with a velocity of ${10}^{10}cm/s.$

1. $0.072\stackrel{\circ }{A}$
2. $0.829\stackrel{\circ }{A}$
3. $0.667\stackrel{\circ }{A}$
4. $1.009\stackrel{\circ }{A}$

Q. The momentum of a particle with de Broglie wavelength $2\stackrel{\circ }{A}$ is:
$(\text{Planck's constant},h=6.62\times {10}^{-34}Js)$

1. $3.31\times {10}^{-24}kgm{s}^{-1}$
2. $3.31\times {10}^{-24}kgcm{s}^{-1}$
3. $9.62\times {10}^{-24}kgm{s}^{-1}$
4. $6.62\times {10}^{-22}kgm{s}^{-1}$

Q. The French physicist Louis de Broglie in 1924 postulated that matter, like radiation, should exhibit a dual behaviour. He proposed the following relationship between the wavelength lambda of a material particle, its linear momentum p and planck constant h.
$\lambda =\frac{h}{p}=\frac{h}{mv}$
The de Broglie relation implies that the wavelength of a particle should decrease as its velocity increases. It also implies that for a given velocity heavier particles should have shorter wavelength than lighter particles. The waves associated with particles in motion are called matter waves or de Broglie waves. These waves differ from the electromagnetic waves as they
$\left(i\right)$ have lower velocities
$\left(ii\right)$ have no electrical and magnetic fields and
$\left(iii\right)$ are not emitted by the particle under consideration.
The experimental confirmation of the de Broglie’s relation was obtained when Davisson and Germer, in 1927, observed that a beam of electrons is diffracted by a nickel crystal. As diffraction is a characteristic property of waves, hence the beam of electron behaves as a wave, as proposed by de Broglie.

Using Bohr’s theory, the transition, so that the electron's de-Broglie wavelength becomes 3 times of its original value in $H{e}^{+}$ ion will be?

1. $2⟶6$
2. $2⟶4$
3. $1⟶4$
4. $1⟶6$

Q. Which one is the wrong statement?


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Q. A particle is moving 3 times faster than the speed of an electron. If the ratio of the wavelength of the particle and the electron is $1.8\times {10}^{-4}$, then the particle is:

1. neutron
2. $\alpha -particle$
3. deutron
4. tritium