Download App

Bohr’s Model and Physics of Atom — Physics STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 SciencePhysicsBohr’s Model and Physics of Atom2 Marks
Question
Electrons are emitted from an electron gun at almost zero velocity and are accelerated by an electric field E through a distance of 1.0m. The electrons are now scattered by an atomic hydrogen sample in ground state. What should be the minimum value of E so that red light of wavelength 656.3nm may be emitted by the hydrogen?
✓

Answer

The given wavelength in Balmer series.
The first line, which requires minimum energy is from $n_1 = 3$ to $n_2= 2$
$\therefore$ The energy should be equal to the energy required for transition from ground state to $n = 3$
i.e., $\text{E}=13.6\Big[1-\Big(\frac{1}{9}\Big)\Big]=12.09\text{eV}$
$\therefore$ Minimum value of electric field $= 12.09v/m = 12.1v/m$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

Physics STD 12 Science question papers→Gujarat Board STD 12 Science question papers→Gujarat Board question paper generator→

Similar questions

X-rays of wavelength $'\lambda'$ fall on a photosensitive surface, emitting electrons. Assuming that the work function of the surface can be neglected, prove that the de Broglie wavelength of electrons emitted will be $\sqrt{\frac{\text{h}\gamma}{2\text{mc}}}.$
→
Assuming the nuclei to be spherical in shape, how does the surface area of a nucleus of mass number $A_1$ compare with that of a nucleus of mass number $A_2?$
→
It is heard sometime that mercury is used in defining the temperature scale because it expands uniformly with temperature. If the temperature scale is not yet defined, is it logical to say that a substance expands uniformly with temperature?
→
The instantaneous voltage from an ac source is given by $\text{E}=300\sin314\text{t};$ what is the rms voltage of the source.
→
Can there be a potential difference between two adjacent conductors carrying the same charge?
→
A tightly-wound, long solenoid has n turns per unit length, a radius r and carries a current i. A particle having charge q and mass m is projected from a point on the axis in a direction perpendicular to the axis. What can be the maximum speed for which the particle does not strike the solenoid ?
→
Explain electricity conduction in intrinsic semi-conductors.
→
State factors on which the resistance of a conductor depends.
→
If current flowing in a circular coil is doubled and radius is halved, then what would be the change in the produced magnetic field at the center of the coil?
→
Water flows through a horizontal tube as shown in If the difference of heights of water column in the vertical tubes is 2cm, and the areas of cross-section at A and B are $4cm^2$ and $2cm^2$ respectively, find the rate of flow of water across any section.
→