Free Printable Modern Physics-03 Matter Waves

1.

Electron has energy of 100 eV what will be its

wavelength

a)

1.2 A

b)

10 A

c)

100 A

d)

1 A

2.

The ratio of wavelength of deutron and proton

accelerated through the same potential difference

will be

a)

$\frac{1}{\sqrt[]{2}}$

b)

$\sqrt[]{2}$

c)

$\frac{1}{2}$

d)

$2$

3.

An electron is accelerated from rest, between two

points A and B at which the potentials are 20V and

40 V respectively. The De Broglie wavelength

associated with the electron at B will be -

a)

0.75 A

b)

7.5 A

c)

2.75 A

d)

2.75 m

4.

The magnitude of De broglie wavelength $\lambda$ of

electron (e), proton (p), neutron (n) and $\alpha$ - particle

all having the same kinetic energy of 1MeV, then which one is correct :

a)

$\lambda_e>\lambda_p>\lambda_n>\lambda_{\alpha}$

b)

$\lambda_e>\lambda_n>\lambda_p>\lambda_{\alpha}$

c)

$\lambda_{\alpha}>\lambda_p>\lambda_n>\lambda_e$

d)

$\lambda_{\alpha}>\lambda_n>\lambda_p>\lambda_e$

5.

The wavelength of very fast moving electron

$\left(v\approx c\right)$ is :

a)

$\lambda=\frac{h}{m_0v}$

b)

$\lambda=\frac{h}{\sqrt[]{2mE}}$

c)

$\lambda^2=\frac{h^2}{\sqrt[]{2mE}}$

d)

$\lambda=\frac{h\sqrt[]{1-\frac{v^2}{c^2}}}{m_0v}$

6.

In davisson-Germer experiment, the filament

emits :-

a)

Photons

b)

Protons

c)

X - rays

d)

Electrons

7.

If given particles are moving with same velocity,

then maximum de-Broglie wavelength for :

a)

Proton

b)

Neutron

c)

Alpha Particle

d)

Beta Particle

8.

If $\lambda_p\ and\ \lambda_{\alpha}$ be the wavelengths of protons and

$\alpha$ -particles of equal kinetic energies, then

a)

$\lambda_p=\frac{\lambda_{\alpha}}{4}$

b)

$\lambda_p=\frac{\lambda_{\alpha}}{2}$

c)

$\lambda_p=\lambda_{\alpha}$

d)

$\lambda_p=2\lambda_{\alpha}$

9.

Electrons used in an electron microscope are

accelerated by a voltage of 25 kV. If the voltage

is increased to 100 kV then the de-Broglie

wavelength associated with the electrons would :

a)

increase by 2 times

b)

decrease by 2 times

c)

decrease by 4 times

d)

increase by 4 times

10.

If velocity of a particle is 3 times of that of electron

and ratio of de brogile wavelength of particle to that

of electron is $1.814\times10^{-4}$ . The particle will be :-

a)

Neutron

b)

Deutron

c)

Alpha

d)

Tritium

11.

Light of wavelength 500 nm is incident on a metal

with work function 2.28 eV. The de Broglie

wavelength of the emitted electron is :-

a)

$\le2.8\times10^{-12}m$

b)

$<2.8\times10^{-12}m$

c)

$<2.8\times10^{-9}m$

d)

$\ge2.8\times10^{-9}m$

12.

An electron with $with\ rest\ mass\ m_0$ moves with a speed

of 0.8C. Its mass when it moves with this speed is :

a)

$m_0$

b)

$\frac{m_0}{6}$

c)

$\frac{5m_0}{3}$

d)

$\frac{3m_0}{5}$

13.

The de Broglie wavelength of an electron moving

with a velocity $1.5\times10^8\ \frac{m}{ses}$ is equal to that of

a photon. The ratio of the kinetic energy of the

electron to the energy of the photon is

a)

$\frac{1}{4}$

b)

$\frac{1}{2}$

c)

$2$

d)

$4$

14.

The de Broglie wavelength of a particle is the same as the wavelength of photon. Then, the photon’s energy is:

a)

equal to the kinetic energy of the particle.

b)

less than kinetic energy of the particle.

c)

greater than kinetic energy of the particle.

d)

nothing can be specified.

15.

A photoelectric material having work function $\phi_0$ is illuminated with light of wavelength $\lambda\left(\lambda<\frac{hc}{\phi_0}\right)$ . The fastest photoelectron has a de Broglie wavelength $\lambda_d$ . A change in the wavelength of the incident light by $\Delta\lambda$ results in change $\Delta\lambda_d$ in $\lambda_d$ . Then the relation $\frac{\Delta\lambda_d}{\Delta\lambda}$ is proportional to

a)

$\frac{\lambda_{d^{ }}^2}{\lambda^2}$

b)

$\frac{\lambda_{d^{ }}^{ }}{\lambda^{ }}$

c)

$\frac{\lambda_{d^{ }}^3}{\lambda^{ }}$

d)

$\frac{\lambda_{d^{ }}^3}{\lambda^2}$

16.

If E and P are the energy and the momentum of

a photon respectively then on reducing the

wavelength of photon -

a)

P and E both will decrease

b)

P and E both will increase

c)

P will increase and E will decrease

d)

P will decrease and E will increase

Modern Physics-03 Matter Waves

Total questions: 16

Worksheet time: 18mins

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