Class 11th

A horizontal bridge is built across a river. A student standing on the bridge throws a small ball vertically upwards with a velocity $4{\mathrm{m}\mathrm{s}}^{-1}$ . The ball strikes the water surface after $4\mathrm{s}$ . The height of bridge above water surface is (Take $\mathrm{g}=$ $10{\mathrm{m}\mathrm{s}}^{-2}$  ):

Consider the following statements (A) and (B) and identify the correct answer.
(A) A zener diode is connected in reverse bias, when used as a voltage regulator.
(B) The potential barrier of p-n junction lies between 0.1 V to 0.3 V.

What is Kolbe's Electrolysis for symmetrical alkenes?

Given below are two statements:
Statement I: A unit formed by the attachment of a base to 1' position of sugar is known as nucleoside
Statement II: When nucleoside is linked to phosphorous acid at 5'-position of sugar moiety, we get nucleotide.

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

Identify the product in the following reaction:

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R:
Assertion A: Helium is used to dilute oxygen in diving apparatus.
Reason R: Helium has high solubility in O₂.

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

Weight (g) of two moles of the organic compound, which is obtained by heating sodium ethanoate with sodium hydroxide in presence of calcium oxide is:

The number of σ bonds, π bonds and lone pair of electrons in pyridine, respectively are

In Lassaigne's extract of an organic compound, both nitrogen and sulphur are present, which gives blood red colour with Fe³⁺ due to the formation of

Match List-I with List-II
List-I: A. Coke, B. Diamond, C. Fullerene, D. Graphite
List-II: I. Carbon atoms are sp³ hybridised, II. Used as a dry lubricant, III. Used as a reducing agent, IV. Cage like molecules

Choose the correct answer from the options given below: