Mix Test - 3...

The electron in a hydrogen atom makes a transition of n₁ to n₂, where n₁ and n₂ are the principal quantum number of the two states. The time period of the electron in the initial state is eight times that in the final state. Then according to Bohr's atomic model, the possible value of n₁ and n₂ are:

The size of an atom is of the order of:

Half life of-a radio-active substance is 2 years. The amount of substance left after 6 years is:

The spectrum of an oil flame is an example for ________.

If there is a H atom, He⁺ ion and Li⁺² ion, then the speed of the electron in the ground state is maximum for:

A radioactive material decays by simultaneous emission of two particles with respective half-lives 1620 and 810 years. The time, in years, after which one-fourth of the material remains is:

Calculate the wavelength of radiation emitted when He+ makes a transition from the state n = 4 to the state n = 3.

The ionization energy of hydrogen atom in excited state is:

If the empirical formula for the observed wavelengths \((\lambda)\) for hydrogen is \(\frac{1}{ \lambda}=\mathrm{R}\left(\frac{1}{3^{2}}-\frac{1}{\mathrm{n}^{2}}\right)\), where '\(\mathrm{n}\)' is integral values higher than 3, then it represents the ________ series.

When an electron jumps from the orbit n = 2 to n = 4, then wavelength of the radiations absorbed will be _________ (R is Rydberg’s constant)

A nucleus with \(\mathrm{Z}=92\) emits the following in a sequence \(\alpha, \alpha, \beta^{-}, \beta^{-}, \alpha, \alpha, \alpha, \alpha, \beta^{-}, \beta^{-}, \alpha, \beta^{+}, \beta^{+}, \alpha\). The \(\mathrm{Z}\) of the resulting nucleus is:

An electron is moving in an orbit of a hydrogen atom at the 4th energy level. Find the number of spectral lines for a transition from here to the ground state.

The Bohr model is applicable to:

Two nuclei have mass numbers in the ratio \(27: 125 .\) What is the ratio of their nuclear radii?

Which of the following spectral series of hydrogen atom is lying in visible electromagnetic wave?

In the Radioactive transformation \(Z \stackrel{\alpha}{\longrightarrow} y \stackrel{\beta}{\longrightarrow} X \stackrel{\beta}{\longrightarrow} R\): the nuclei of \(\mathrm{R}\) and \(\mathrm{Z}\) are:

Which of the following statement(s) are correct for the Bohr model?

Wavelengths of extreme lines of Paschen series for hydrogen is:

In the spectrum of hydrogen, the ratio of the longest wavelength in the Lyman series to the longest wavelength in the Balmer series is:

What is the energy of an electron that is revolving in the second orbit of the hydrogen?

When an electron in hydrogen atom is excited, from its 3rd to 4th stationary orbit, the change in angular momentum of electron is:

Half-life period for a first order reaction is 1244sec. The specific rate constant of the reaction is:

Which series of hydrogen spectrum corresponds to ultraviolet region?

The nucleus of which of the following atoms whose atomic mass numbers '\(A\)' are given in the options would have the highest binding energy per nucleon?

The three stable isotopes of neon: \({ }_{10}^{20} \mathrm{Ne},{ }_{10}^{21} \mathrm{Ne}\) and \({ }_{10}^{22} \mathrm{Ne}\) have respective abundances of \(90.51 \%, 0.27 \%\) and \(9.22 \%\). The atomic masses of the three isotopes are \(19.99 \mathrm{u}, 20.99 \mathrm{u}\) and \(21.99 \mathrm{u}\) respectively. Obtain the average atomic mass of neon.

Successive emission of an α-particle and two β-particles by an atom of a radioactive element results in the formation of its:

The relation between half-life\((t_{\frac{1}{2}})\) of a radioactive sample and its mean life is:

What is the ratio of the wavelength of photon released when the electron jumps from 5th to 4th orbit of a hydrogen atom and then from 4th to the ground state?

Calculate the Bohr radius of 3rd orbit of Be³⁺.

In a Rutherford's α-scattering experiment with thin gold foil, 8100 scintillations per minute are observed at an angle of 60°. What will be the number of scintillations per minute at an angle of 120°?