An $\alpha ‐$particle moves in a circular path of radius 0.83 cm in the presence of a magnetic field of 0.25 $Wb/{m}^{2}.$The de-Broglie wavelength associated with the particle will be

(a)                                                    (b)

(c)                                                  (d)

Concept Questions :-

De-broglie wavelength
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

If the momentum of an electron is changed

by p, then the de-Broglie wavelength

associated with it changes by 0.5%. The

initial momentum of the electron will be

(a) 200p

(b) 400p

(c) $\frac{\mathrm{P}}{200}$

(d) 100p

Concept Questions :-

De-broglie wavelength
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

In the Davisson and Germer experiment, the

velocity of electrons emitted from the electron

gun can be increased by

(a) increasing the filament current

(b) decreasing the filament current

(c) decreasing the potential difference between

the anode and filament

(d) increasing the potential difference  between

the anode and filament

Concept Questions :-

Davisson and Germer experiment
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

A radioactive nucleus of mass M emits a photon

of frequency $\nu$ and the nucleus recoils. The recoil

energy will be:

(a)

(b) zero

(C) h$\nu$

(d) ${\mathrm{Mc}}^{2}-\mathrm{h\nu }$

Concept Questions :-

De-broglie wavelength
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

In photoelectric emission process from a metal

of work function 1.8 eV, the kinetic energy of most

energetic electrons is 0.5 eV. The corresponding

stopping potential is

(a) 1.2 V

(b) 0.5 V

(c)2.3 V

(d) 1.8 V

Concept Questions :-

Photoelectric effect experiment
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

Light of two different frequencies whose

photons have energies 1 eV and 2.5 eV

respectively illuminate a metallic surface

whose function is 0.5 eV successively.

Ratio of maximum speeds of emitted

electrons will be

(a) 1:2

(b) 1:1

(c) 1:5

(d) 1:4

Concept Questions :-

Photoelectric effect experiment
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

Photoelectric emission occurs only when the incident light has more than a certain minimum

1. wavelength

2. intensity

3. frequency

4. power

Concept Questions :-

Photoelectric effect experiment
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

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

1. decrease by 2 times

2. decrease by 4 times

3. increase by 4 times

4. increase by 2 times

Concept Questions :-

De-broglie wavelength
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

The threshold frequency for a photo-sensitive metal is  If the light of frequency  is incident on this metal, the cut-off voltage for the photo-electric emission is nearly:

1. 2 V                                        2. 3 V

3. 5 V                                         4. 1 V

Concept Questions :-

Photoelectric effect experiment
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

An electron in the hydrogen atom jumps from nth excited state  to the ground state. The wavelength so emitted illuminates a photosensitive material having work function 2.75 eV. If the stopping potential of the photo-electron is 10V, the value of n is

1. 3                                    2. 4

3. 5                                    4. 2

Concept Questions :-

Einstein photo-electric equation