NEET 2020 Phase 1 | Dual Nature of Radiation and Matter Question 18 | Physics

Light with an average flux of 20 W/cm² falls on a non-reflecting surface at normal incidence having surface area 20 cm². The energy received by the surface during time span of 1 minute is :

12 $$ \times $$ 10³ J

24 $$ \times $$ 10³ J

48 $$ \times $$ 10³ J

10 $$ \times $$ 10³ J

NEET 2020 Phase 1

MCQ (Single Correct Answer)

-1

An electron is accelerated from rest through a potential difference of V volt. If the de-Broglie wavelength of the electron is 1.227 $$ \times $$ 10^-2 nm, the potential difference is :

10² V

10³ V

10⁴ V

10 V

NEET 2019

MCQ (Single Correct Answer)

-1

An electron is accelerated through a potential difference of 10,000 V. Its de Broglie wavelength is (nearly) : (m_e = 9 $$ \times $$ 10^–31 kg)

12.2 × 10^–12 m

12.2 × 10^–13 m

12.2 × 10^–14 m

12.2 nm

NEET 2018

MCQ (Single Correct Answer)

-1

An electron of mass m with an initial velocity $$\overrightarrow v = {v_0}\widehat i$$ (v₀ > 0) enters an electric field $$\overrightarrow E = - {\overrightarrow E _0}\widehat i$$ (E₀ = constant > 0) at t = 0. If $$\lambda $$₀ is its de-Broglie wavelength initially, then its de- Broglie wavelength at time t is

$${{{\lambda _0}} \over {\left( {1 + {{e{E_0}} \over {m{v_0}}}t} \right)}}$$

$${{\lambda _0}\left( {1 + {{e{E_0}} \over {m{v_0}}}t} \right)}$$

$$\lambda $$₀t

$$\lambda $$₀

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