AIEEE 2008 | Dual Nature of Radiation Question 155 | Physics

Wave property of electrons implies that they will show diffraction effects. Davisson and Germer demonstrated this by diffracting electrons from crystals. The law governing the diffraction from a crystal is obtained by requiring that electron waves reflected from the planes of atoms in a crystal interfere constructively (see figure). AIEEE 2008 Physics - Dual Nature of Radiation Question 148 English

AIEEE 2008 Physics - Dual Nature of Radiation Question 148 English

If a strong diffraction peak is observed when electrons are incident at an angle $$'i'$$ from the normal to the crystal planes with distance $$'d'$$ between them (see figure), de Broglie wavelength $${\lambda _{dB}}$$ of electrons can be calculated by the relationship ($$n$$ is an integer)

$$d\,\sin \,i = n{\lambda _{dB}}$$

$$2d\,\cos \,i = n{\lambda _{dB}}$$

$$2d\,\sin \,i = n{\lambda _{dB}}$$

$$d\,\cos \,i = n{\lambda _{dB}}$$

AIEEE 2007

MCQ (Single Correct Answer)

-1

Photon of frequency $$v$$ has a momentum associated with it. If $$c$$ is the velocity of light, the momentum is

$$hv/c$$

$$v/c$$

$$h$$ $$v$$ $$c$$

$$hv/{c^2}$$

AIEEE 2006

MCQ (Single Correct Answer)

-1

The threshold frequency for a metallic surface corresponds to an energy of $$6.2$$ $$eV$$ and the stopping potential for a radiation incident on this surface is $$5V.$$ The incident radiation lies in

ultra-violet region

infra-red region

visible region

$$x$$-ray region

AIEEE 2006

MCQ (Single Correct Answer)

-1

The time taken by a photoelectron to come out after the photon strikes is approximately

$${10^{ - 4}}\,s$$

$${10^{ - 10}}\,s$$

$${10^{ - 16}}\,s$$

$${10^{ - 1}}\,s$$