NEET 2017 | Dual Nature of Radiation and Matter Question 20 | Physics

NEET 2017

MCQ (Single Correct Answer)

-1

The de-Broglie wavelength of a neutron in thermal equilibrium with heavy water at a temperature T (kelvin) and mass m, is

$${h \over {\sqrt {3mkT} }}$$

$${{2h} \over {\sqrt 3 mkT}}$$

$${{2h} \over {\sqrt {mkT} }}$$

$${h \over {\sqrt {mkT} }}$$

NEET 2016 Phase 2

MCQ (Single Correct Answer)

-1

Photons with energy 5 eV are incifent on a cathode C in a photoelectric cell. The maximum energy of emitted photoelectrons is 2 eV. When photons of energy 6 eV are incident on C, no photoelectrons will reach the anode A, if the stopping potential of A relative to C is

+ 3 V

+4 V

$$-$$1 V

$$-$$3 V

NEET 2016 Phase 2

MCQ (Single Correct Answer)

-1

Electrons of mass m with de-Broglie wavelength $$\lambda $$ fall on the target in an X-ray tube. The cutoff wavelength ($$\lambda $$₀) of the emitted X-ray is

$$\lambda $$₀ = $${{2mc{\lambda ^2}} \over h}$$

$${\lambda _0} = {{2h} \over {mc}}$$

$${\lambda _0} = {{2{m^2}{c^2}{\lambda ^3}} \over {{h^2}}}$$

$${\lambda _0} = \lambda $$

NEET 2016 Phase 1

MCQ (Single Correct Answer)

-1

When a metallic surface is illuminated with radiation of wavelength $$\lambda $$, the stopping potential is V. If the same surface is illuminated with radiation of wavelength 2 $$\lambda $$, the stopping potential is $${V \over 4}$$. The threshold wavelength for the metallic surface is

$${5 \over 2}\lambda $$

3$$\lambda $$

4$$\lambda $$

5$$\lambda $$

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