Class 12th

A small coin is resting on the bottom of a beaker filled with liquid. A ray of light from the coin travels upto the surface of the liquid and moves along its surface. How fast is the light travelling in the liquid?

Statement – I : Phenol is converted to benzene on heating with zinc dust.

Statement – II: Chromic acid oxidises phenol to benzoquinone.

In light of the above statements, choose the correct answer.

Consider the following reaction sequence

Which of the following is true?

The compound which is most easily soluble in aqueous alkali is

Statement A: In intrinsic semiconductors, conductivity is mainly due to the breakage of covalent bonds.

Statement B: In extrinsic semiconductors, the conductivity is mainly due to the addition of impurities.

An AND gate can be prepared by repetitive use of

a) NOT gate (b) OR gate            (c) NAND gate                 (d) NOR gate

Which of the following is not a common component of photochemical smog?

When $Mn{O}_2$ is fused with potassium hydroxide in presence of $KN{O}_3$ , the deep green compound obtained is

Consider the following statements

(I)  Histamine is a potent vasodilator

(II) Brompheniramine is an antihistamine

(III) Tranquilizers and analgesics are neurologically active drugs

The correct statements among the following are