Atoms practice · Mixed difficulty

Which of the relation is correct between time period and number of orbits while an electron is revolving in an orbit

When an $\mathrm{\alpha }$ - particle of mass ‘m’ moving with the velocity ‘v’ bombards on a heavy nucleus of charge ‘Ze’, its distance of closest approach from the nucleus depends on m as:

What is the ratio of the circumference of the first Bohr orbit for the electron in the hydrogen atom to the de Broglie wavelength of electrons having the same velocity as the electron in the first Bohr orbit of the hydrogen atom?

The ratio of minimum to maximum wavelength in Balmer series is

In Bohr's theory for hydrogen-like atoms:

If an electron is moving in the $n\,th$ orbit of the hydrogen atom, then its velocity ${V_n}$ for the $n\,th$ orbit is given as

de Broglie wavelength associated with the orbital electron in nth orbit of hydrogen atom is approximately given by

The absorption transitions between the first and the fourth energy states of hydrogen atom are $\mathrm{3}$. The emission transitions between these states will be

Assertion: The phenomenon of X-ray production is basically inverse of photoelectric effect.

Reason: X-rays are electromagnetic waves.

The angular momentum of electron in ${n^{\mathrm{th}}}$ orbit is given by

Let $E_n=\frac{-1}{8 \varepsilon_0^2 n^2 h^2}$ be the energy of the $n$th level of ${H}$-atom. If all the ${H}$-atoms are in the ground state and radiation of frequency $\left(E_2-E_1\right) / h$ falls on it then

$X$-rays beam can be deflected by

The spectral series of the hydrogen spectrum that lies in the ultraviolet region is the

An X-ray machine is operated at 40 kV. The short wavelength limit of continuous X-rays will be $\left( {h = 6.63 \times {{10}^{ - 34}}Js,\;c\; = \;3 \times {{10}^8}\;m{s^{ - 1}},\;e = 1.6 \times {{10}^{ - 19}}\;C} \right)$

In which of the following systems will the radius of the first orbit $\left( {n = 1} \right)$ be minimum

Number of spectral lines in hydrogen atom is

In Rutherford experiment on $\alpha -$ray scattering the number of particles scattered at ${90^\mathrm{o}}$ be 28 per minute. Then the number of particles scattered per minute by the same foil but are at ${60^\mathrm{o}}$ are.

The angular momentum of electron in $n^{\text {th }}$ orbit of $\mathrm{H}$-atom is $L$. The magnitude of magnetic moment of the electron is (Symbols have their usual meanings)

According to Bohr’s theory the radius of electron in an orbit described by principle quantum number $n$ and atomic number $Z$ is proportional to

Assertion (A): Study of emission spectra of a material can serve as a finger print for identification of the material.

Reason (R): Every element has its characteristic spectrum of emission.

Consider the following two statements $\mathrm{A}$ and $\mathrm{B}$ and identify the correct choice in the given answers

A: Line spectra is due to atoms in gaseous state

B: Band spectra is due to molecules

In a hypothetical Bohr hydrogen, the mass of the electron is doubled. The energy ${E_0}$ and the radius ${r_0}$ of the first orbit will be (${a_0}$ is the Bohr radius)

Assertion (A): A laser beam of $0.2 \mathrm{~W}$ can drill holes through a metal sheet whereas a $1000 \mathrm{~W}$ torch light cannot.

Reason (R): The frequency of laser light in much higher than that of torch light.

The number of different wave lengths may be observed in the spectrum from a hydrogen sample if the atoms are excited to fourth excited state is

If an electron oscillates at a frequency of $1\;GHz$ it gives

Minimum wavelength of $X$-ray produced depends on accelerating potential $V$ between cathode and anode as

The angular momentum of an electron in a hydrogen atom is proportional to

What is the wavelength of the most energetic photon emitted in the Balmer series of the hydrogen atom?

The energy of the characteristic X-ray photon in Coolidge tube comes from

Assertion: For the scattering of $\alpha$-particles at large angles, only the nucleus of the atom is responsible.
Reason: Nucleus is very heavy in comparison to electrons.