Energy Level | MCQs

Explanation

 The lifetime of an electron in a metastable state is significantly longer than in an ordinary excited state, typically by 10³ to 10⁵ times. 

Ordinary excited states have lifetimes on the order of 10⁻⁸ seconds. 

Metastable states have lifetimes that can range from microseconds to milliseconds and even longer, being orders of magnitude longer than typical excited states.

Therefore, options like 10³ or 10⁵ are appropriate estimations for how much longer a metastable state lifetime is compared to an ordinary excited state. 

Explanation

Electronic transitions occur when electrons jump between energy levels in an atom.

These transitions typically release photons in the infrared, visible, or ultraviolet regions — depending on the energy difference.

γ-radiations (gamma rays) are high-energy photons emitted from the nucleus, not from electronic transitions.

They are associated with nuclear reactions, not electronic energy level changes.

Explanation

The energy required to excite an electron from the second orbit to the third orbit is:

ΔE = 13.6Z^2(1/4 - 1/9) eV

Given ΔE = 42.7 eV:

42.7 = 13.6Z^2(1/4 - 1/9)

Solving for Z:

Z = 4

Explanation

• The removal of the 7th electron from an element of Group VI of the periodic table needs three times more energy than the removal of the 6th electron.
• This is because the ionization energy increases as you remove more electrons from an atom, and this is due to the fact that the electrons that are left behind are more strongly attracted to the positive nucleus.

Explanation

In quantum mechanics, an electron in a one-dimensional infinite potential well (also called a "quantum box" or "particle in a box") has discrete energy levels given by:

$$E_n = frac{n^2 h^2}{8mL^2}$$8mL^2​

Where:

• $n$ = quantum number (for ground state$n=1$)

• $h$ = Planck’s constant

• $m$ = mass of the electron

• $L$ = width of the box

▶ These energy levels depend only on the physical parameters (like mass, size of the box), not on temperature.

The ground state energy (lowest possible energy) is:

E1​=h^2/8mL^2​

Explanation

The potential through which an electron should be accelerated to lift an atom's electron from the ground state to a higher state is known as excitation potential.

This energy excites the electron without completely removing it from the atom.

Explanation

The Lyman series falls in the ultraviolet region.

It corresponds to electronic transitions in a hydrogen atom where the electron drops to the n=1 energy level, emitting ultraviolet radiation.

Explanation

If an electron transitions from n=6 to n=7, the percentage increase in radius is approximately 33%.

Explanation

Explanation

Energy is carried by Stationary Wave. 

 Violet light has highest energy.