Mark the correct options:

Download App

MCQ

A
An atom with a vacancy has smaller energy that a neutral atom.
B
K X-ray is emitted when a hole makes a jump from the K shell to some other shell.
C
The wavelength of K X-ray is smaller than the wavelength of L X-ray of the same material.
D
The wavelength of $\text{K}_\alpha$ X-ray is smaller than the wavelength of $\text{K}_\beta$ X-ray of the same material.

✓

Answer

K X-ray is emitted when a hole makes a jump from the K shell to some other shell.
The wavelength of K X-ray is smaller than the wavelength of L X-ray of the same material.

Explanation:

Energy of a vacant atom is higher than that of a neutral atom.

Hence, option (a) is incorrect.

K X-ray is emitted when an electron makes a jump to the K shell from some other shell. As a result, a positive charge hole is created in the outer shell. As the electron continuously moves to the K shell, the hole moves from the K shell to some other shell.

Hence, option (b) is correct.

K X-ray is emitted due to the transition of an electron from the L or M shell to the K shell and L X-ray is emitted due to the transition of an electron from the M or N shell to the L shell. The energy involved in the transition from the L or M shell to the K shell is higher than the energy involved in the transition from the M or N shell to the L shell. Since the energy is inversely proportional to the wavelength, the wavelength of the K X-ray is smaller than the wavelength of the L X-ray of the same material. Hence, option (c) is correct.

If E_K, E_L and E_M are the energies of K, L and M shells, respectively, then the wavelength of $\text{K}_\alpha$ X-ray $(\lambda_1)$ is given by

$\lambda_1=\frac{\text{hc}}{\text{E}_\text{K}-\text{E}_\text{L}}$

Here,

h = Planck's constant

c = Speed of light

Wavelength of the $\text{K}_\beta$ x-ray $(\lambda_2)$ is given by

$\lambda_2=\frac{\text{hc}}{\text{E}_\text{K}-\text{E}_\text{M}}$

As the difference of energies (E_K - E_M) is more than (E_K- E_L), $\lambda_2$ is less than$\lambda_1$.

Hence, option (d) is not correct.

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

More "M.C.Q (1 Marks)" from Dual Nature of Radiation and Matter→Dual Nature of Radiation and Matter — all question types→Physics STD 12 Science question papers→Gujarat Board STD 12 Science question papers→Gujarat Board question paper generator→

Similar questions

AB and CD are long straight conductor, distance d apart, carrying a current I. The magnetic field at the midpoint of BC is

(a)

(b)

(c)

(d)

→

During the nuclear fusion reaction

(a) A heavy nucleus breaks into two fragments by itself

(b) A light nucleus bombarded by thermal neutrons breaks up

(d) Two light nuclei combine to give a heavier nucleus and possibly other products

→

Given three equal resistors, how many different combination of all the three resistors can be made

(a) Six

(b) Five

(d) Three

→

The ratio of contributions made by the electric field and magnetic field components to the intensity of an EM wave is:

→

A conducting square loop of side l and resistance R moves in its plane with a uniform velocity u perpendicular to one of its sides. A uniform and constant magnetic field B exists along the perpendicular to the plane of the loop as shown in figure. The current induced in the loop is:

$\frac{\text{Blv}}{\text{R}}$ clockwise.
$\frac{\text{Blv}}{\text{R}}$ anticlockwise.
$\frac{2\text{Blv}}{\text{R}}$ anticlockwise.
$\text{Zero.}$

→

Which of the following statement is not true regarding Einsteins mass energy relation?

→

Electrical energy $U _0$ is stored in a charged parallel plate capacitor. On increasing the distance between the plates of a capacitor, double to initial distance the electrical energy will be :

→

The plate characteristic curve of a diode in space charge limited region is as shown in the figure. The slope of curve at point P is 5.0 mA/V. The static plate resistance of diode will be