JEE Main 2019 (Online) 8th April Morning Slot | Dual Nature of Radiation Question 90 | Physics

JEE Main 2019 (Online) 8th April Morning Slot

MCQ (Single Correct Answer)

-1

Two particles move at right angle to each other. Their de-Broglie wavelengths are $$\lambda _1$$ and $$\lambda _2$$ respectively. The particles suffer perfectly inelastic collision. The de-Broglie wavelength $$\lambda _2$$ of the final particle, is given by :

$$\lambda = {{{\lambda _1} + {\lambda _2}} \over 2}$$

$${1 \over {{\lambda ^2}}} = {1 \over {\lambda _1^2}} + {1 \over {\lambda _2^2}}$$

$$\lambda = \sqrt {{\lambda _1}{\lambda _2}} $$

$${2 \over \lambda } = {1 \over {{\lambda _1}}} + {1 \over {{\lambda _2}}}$$

JEE Main 2019 (Online) 12th January Evening Slot

MCQ (Single Correct Answer)

-1

In a Frank-Hertz experiment, an electron of energy 5.6 eV passes through mercury vapour and emerges with an energy 0.7 eV. The minimum wavelength of photons emitted by mercury atoms is close to :

2020 nm

250 nm

1700 nm

220 nm

JEE Main 2019 (Online) 12th January Evening Slot

MCQ (Single Correct Answer)

-1

When a certain photosensitive surface is illuminated with monochromatic light of frequency v, the stopping potential for the current is –V₀/2. When the surface is illuminated by monochromatic light of frequency v/2, the stopping potential is – V₀. The threshold frequency for photoelectric emission is :

2$$v$$

$${4 \over 3}v$$

$${{3v} \over 2}$$

$${{5v} \over 3}$$

JEE Main 2019 (Online) 12th January Morning Slot

MCQ (Single Correct Answer)

-1

A particle A of mass 'm' and charge 'q' is accelerated by a potential difference of 50 V. Another particle B of mass ' 4 m' and charge 'q' is accelerated by a potential difference of 2500 V. The ratio of de-Broglie wavelengths $${{{\lambda _A}} \over {{\lambda _B}}}$$ is close to :

4.47

10.00

14.14

0.07

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