JEE Main 2019 (Online) 10th January Evening Slot | Dual Nature of Radiation Question 96 | Physics

JEE Main 2019 (Online) 10th January Evening Slot

MCQ (Single Correct Answer)

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A metal plate of area 1 $$ \times $$ 10^–4 m² is illuminated by a radiation of intensity 16 mW/m². The work function of the metal is 5 eV. The energy of the incident photons is 10 eV and only 10% of it produces photo electrons. The number of emitted photoelectrons per second and their maximum energy, respectively, will be

10¹⁴ and 10 eV

10¹² and 5 eV

10¹¹ and 5 eV

10¹⁰ and 5 eV

JEE Main 2019 (Online) 9th January Evening Slot

MCQ (Single Correct Answer)

-1

The magnetic field associated with a light wave is given, at the origin, by B = B₀ [sin(3.14 $$ \times $$ 10⁷)ct + sin(6.28 $$ \times $$ 10⁷)ct]. If this light falls on a silver plate having a work function of 4.7 eV, what will be the maximum kinetic energy of the photo electrons ?
(c = 3 $$ \times $$ 10⁸ ms^$$-$$1, h = 6.6 $$ \times $$ 10^$$-$$34J-s)

6.82 eV

12.5 eV

8.52 eV

7.72 eV

JEE Main 2019 (Online) 9th January Morning Slot

MCQ (Single Correct Answer)

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Surface of certain metal is first illuminated with light of wavelength $$\lambda $$₁ = 350 nm and then, by light of wavelength $$\lambda $$₂ = 540 nm. It is found that the maximum speed of the photo electrons in the two cases differ by a factor of 2. The work function of the metal (in eV) is close to :

(Energy of photon n = $${{1240} \over {\lambda (in\,mm)}}$$eV)

1.8

2.5

5.6

1.4

JEE Main 2018 (Online) 16th April Morning Slot

MCQ (Single Correct Answer)

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The de-Broglie wavelength ($$\lambda $$_B) associated with the electron orbiting in the second excited state of hydrogen atom is related to that in the ground state ($$\lambda $$_G) by :

$$\lambda $$_B = 2$$\lambda $$_G

$$\lambda $$_B = 3$$\lambda $$_G

$$\lambda $$_B = $$\lambda $$_G/2

$$\lambda $$_B = $$\lambda $$_G/3

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