Class 12th

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).

Assertion (A): In a particular point defect, an ionic solid is electrically neutral, even if few of its cations are missing from it unit cells.
Reason (R): In an ionic solid, Frenkel defect arises due to dislocation of cation from its lattice site to interstitial site, maintaining overall electrical neutrality.

In the light of the above statements, choose the most appropriate answer from the options given below:

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).

Assertion (A): ICl is more reactive than I?.
Reason (R): I-Cl bond is weaker than I-I bond.

In the light of the above statements, choose the most appropriate answer from the options given below:

Let ${\mathrm{T}}_1$ and ${\mathrm{T}}_2$ be the energy of an electron in the first and second excited states of hydrogen atom, respectively. According the Bohr's model of an atom, the ratio ${\mathrm{T}}_1:{\mathrm{T}}_2$  is :

Given below are two statements:

Statement I: Photovoltaic devices can convert optical radiation into electricity.

Statement II: Zener diode is designed to operate under reverse bias in breakdown region.

In the light of the above statements, choose the most appropriate answer from the options given below:

A full wave rectifier circuit consists of two p-n junction diodes, a centre-tapped transformer, capacitor and a load resistance. Which of these components remove the ac ripple from the rectified output

The half life of a radioactive substance is 20 minutes. In how much time, the activity of substance drops to $(1/16{)}^{\text{th}}$  of its initial value?

In the given nuclear reaction, the elements X is: ${}_{11}^{22}\mathrm{N}\mathrm{a}\to \mathrm{X}+{\mathrm{e}}^{+}+v$

In hydrogen spectrum, the shortest wavelength in the Balmer series is $\lambda$ . The shortest wavelength in the Bracket series is :

The work functions of Caesium (Cs), Potassium (K) and Sodium (Na) are $2.14\mathrm{e}\mathrm{V},2.30\mathrm{e}\mathrm{V}$ and $2.75\mathrm{e}\mathrm{V}$ respectively. If incident electromagnetic radiation has an incident energy of $2.20\mathrm{e}\mathrm{V}$ , which of these photosensitive surfaces may emit photoelectrons?

For Young's double slit experiment, two statements are given below:

Statement I: If screen is moved away from the plane of slits, angular separation of the fringes remains constant.

Statement II: If the monochromatic source is replaced by another monochromatic source of larger wavelength, the angular separation of fringes decreases.

In the light of the above statements, choose the correct answer from the options given below: