Class 12th

Match List – I with List – II:
| List - I (Example of Colloids) | List - II (Classification) |
| (a) Cheese            | (i) dispersion of liquid in liquid |
| (b) Pumice stone | (ii) dispersion of liquid in gas |
| (c) Hair cream      | (iii) dispersion of gas in solid |
| (d) Cloud              | (iv) dispersion of liquid in solid |
Choose the most appropriate answer from the option given below:

Which one of the following metal complexes is most stable?

The spin only magnetic moments (in BM) for free Ti³?, V²? and Sc³? ions respectively are
(At. No. Sc: 21; Ti:22; V:23)

Maleic anhydride
Maleic anhydride can be prepared by:

The nuclear activity of a radioactive element becomes (1/8)ᵗʰ of its initial value in 30 years. The half –life of radioactive element is __________ years.

In a semiconductor, the number density of intrinsic charge carriers at 27°C is 1.5 * 10¹? / m³. If the semiconductor is doped with impurity atom, the hole density increases to 4.5*10²² / m³. The electron density in the doped semiconductor is __________ x 10? / m³.

A system consists of two types of gas molecules A and B having same number density 2*10²⁵ / m³. The diameter of A and B are 10 Å and 5 Å respectively. They suffer collision at room temperature. The ratio of average distance covered by the molecule A to that of B between two successive collision is __________ x10⁻².

A message single of frequency 20 kHz and peak voltage of 20 volt is used to modulate a carrier wave of frequency 1 MHz and peak voltage of 20 volt. The modulation index will be __________.

A light beam of wavelength 500 nm is incident on a metal having work function of 1.25 eV, placed in a magnetic field of intensity B. The electrons emitted perpendicular to the magnetic field B, with maximum kinetic energy are bent into circular arc of radius 30cm. The value of B is __________ x x 10⁻⁷ T
Given hc = 20 * 10?²? J-m, mass of electron = 9 * 10⁻³¹ kg

Two circuits are shown in the figure (a) & (b). At a frequency of __________ rad /s the average power dissipated in one cycle will be same in both the circuits.