Tag: matter waves

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Multiple choice physics dual nature of matter and radiation davisson and germer experiment and its conclusion matter waves wave nature of matter

In davisson-Germer experiment an electron beam accelerated with $54$ volt is diffracted at an angle of $$ by a nickel crystal and produced first diffraction maxima. The interatomic distance in Nickel crystal is  

  1. $1\mathop A\limits^0 $

  2. $2\mathop A\limits^0 $

  3. $2.15\mathop A\limits^0 $

  4. $3.12\mathop A\limits^0 $
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Using the Davisson-Germer formula with 54 eV electrons (λ ≈ 1.67 Å) and the standard diffraction condition for nickel crystals, the interatomic distance is calculated to be approximately 2.15 Å, which matches the known lattice spacing of nickel.

Multiple choice physics dual nature of matter and radiation davisson and germer experiment and its conclusion matter waves wave nature of matter

In Davisson-Germer experiment an electron bear of energy 75 eV falls normally on the surface via crystal If the maxima of order I. _obtained at an angIe $45^o$ to the direction incidentr then the interatomic distance in the lattice palne of the cystal will be-

  1. $1.0 \ AA$

  2. $1.56 \ AA$

  3. $1.20 \ AA$

  4. $0.83 \ AA$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$\begin{array}{l} nb=2d\sin  \theta  \ \frac { { 12.27 } }{ { \sqrt { 75 }  } } =2d\sin  45 \ 1.41=2d\times \frac { 1 }{ { \sqrt { 2 }  } }  \ \therefore d=\frac { { 1.41 } }{ { 1.41 } } =1A^{ ^{ \circ  } } \end{array}$

Hence, the option $A$ is the correct answer.

Multiple choice physics dual nature of matter and radiation davisson and germer experiment and its conclusion matter waves wave nature of matter

The wavelength of $L _\alpha$ line in $X-ray$ spectrum of $Pt^{78}$ is $1.32\mathring { A } $ then wavelength of $L _\alpha $ line $X-ray$ spectrum of another unknown element is $4.17\mathring { A } .$ If screening constant for $L _\alpha $ line is $7.4,$ then atomic number of the unknown element is -

  1. $78$

  2. $47$

  3. $40$

  4. $35$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Moseley's Law for X-rays: 1/lambda = R * (Z-sigma)^2 * (1/n1^2 - 1/n2^2). Since the transition is the same (L_alpha), (Z1-sigma)^2 * lambda1 = (Z2-sigma)^2 * lambda2. Plugging in Z1=78, sigma=7.4, lambda1=1.32, lambda2=4.17, we solve for Z2.

Multiple choice physics dual nature of matter and radiation davisson and germer experiment and its conclusion matter waves wave nature of matter

Davisson and Germer studied the diffraction from crystal of beams of

  1. Alpha particles

  2. Protons

  3. Electrons

  4. Photons
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Davisson and Germer's actual objective was to study the surface of a piece of nickel by directing a beam of electrons at the surface and observing how many electrons bounced off at various angles. They expected that because of the small size of electrons, even the smoothest crystal surface would be too rough and thus the electron beam would experience diffuse reflection.

During the experiment an accident occurred and air entered the chamber, producing an oxide film on the nickel surface. To remove the oxide, Davisson and Germer heated the specimen in a high temperature oven, not knowing that this affected the formerly polycrystalline structure of the nickel to form large single crystal areas with crystal planes continuous over the width of the electron beam. 

When they started the experiment again and the electrons hit the surface, they were scattered by atoms which originated from crystal planes inside the nickel crystal.In 1925, they generated a diffraction pattern with unexpected peaks.

So, the answer is option (C).

Multiple choice physics dual nature of matter and radiation davisson and germer experiment and its conclusion matter waves wave nature of matter

Electrons can be diffracted (Davis-son and German's expt.).

  1. Yes, as their wave is transverse.

  2. Yes, as their wave is longitudinal

  3. No, as their wave is longitudinal

  4. No, as they travel in a straight line.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

As electron waves oscillation is confined in one orientation only, therefore  it cannot be polarized.

Multiple choice physics dual nature of matter and radiation davisson and germer experiment and its conclusion matter waves wave nature of matter

In Davisson-Germer experiment, intensity was maximum for accelerating voltage equal to

  1. $44$

  2. $54$

  3. $64$

  4. $74$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In Davisson-Germer experiment, maximum intensity of diffracted electron beam was found at different angles by varying the applied voltage to the electron gun. The highest intensity was observed at an angle $\phi =50^o$ with a voltage of $54 V$, giving the electron a kinetic energy of $54eV$.

Multiple choice physics dual nature of matter and radiation davisson and germer experiment and its conclusion matter waves wave nature of matter

In Davisson-Germer experiment, intensity was maximum for scattering angle equal to

  1. $40$

  2. $50$

  3. $60$

  4. $70$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In Davisson -Germer experiment, it was observed that the intensity of the scattered electron beam depends on the scattering angle $\phi$. Also, it Davisson and Germer observed that the maximum intensity was detected when the scattering angle was  $50^o$.

Multiple choice physics dual nature of matter and radiation davisson and germer experiment and its conclusion matter waves wave nature of matter

The Davisson-Germer experiment was performed by varying the accelarating voltage from __ V to __ V.

  1. $44, 68$

  2. $54, 78$

  3. $44, 58$

  4. $85, 100$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In Davisson-Germer experiment, maximum intensity of diffracted electron beam was found at different angles by varying the applied voltage to the electron gun from $44V$ to $68V$. The highest intensity was observed at an angle $\phi =50^o$ with a voltage of $54 V$, giving the electron a kinetic energy of $54eV$.