NEET 2016 Phase 1 | Dual Nature of Radiation and Matter Question 27 | Physics

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$$\lambda $$

AIPMT 2015

MCQ (Single Correct Answer)

-1

A photoelectric surface is illuminated successively by monochromatic light of wavelength $$\lambda $$ and If the maximum kinetic energy of the emitted photoelectrons in the second case is 3 times that in the first case, the work function of the surface of the material is
(h = Planck's constant, C = speed of light)

$${{2hc} \over \lambda }$$

$${{hc} \over {3\lambda }}$$

$${{hc} \over {2\lambda }}$$

$${{hc} \over \lambda }$$

AIPMT 2015

MCQ (Single Correct Answer)

-1

Light of wavelength 500 nm is incifent on a metal with work function 2.28 eV. The de Broglie wavelength of the emitted electron is

$$ \ge $$ 2.8 $$ \times $$ 10^$$-$$9 m

$$ \le $$ 2.8 $$ \times $$ 10^$$-$$12 m

< 2.8 $$ \times $$ 10^$$-$$10 m

< 2.8 $$ \times $$ 10^$$-$$9 m

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