# Class 11 NCERT Solutions

#### Chemistry Chapter-01: Some Basic Concepts of Chemistry

Q1. Find out the value of molecular weight of the given compounds:

(i) $$CH_{4}$$ (ii)$$H_{2}O$$ (iii)$$CO_{2}$$

#### Chemistry Chapter-02: Structure of Atom

Q.1. (a)Figure the quantity of electrons which will together measure one gram.

(b)Compute the mass and charge of one mole of electrons.

#### Chemistry Chapter-03: Classification of Elements and Periodicity in Properties

Q-1) What is the basic theme of organisation in the periodic table?

Ans.) It is to characterize the elements in periods and groups as per their properties. So, this course of action makes the investigation of elements and compounds of elements in a simple one and methodical way. In this periodic table, elements with comparative properties are set in a similar groups.

#### Chemistry Chapter-04: Chemical Bonding and Molecular Structure

Q-1) Explain Chemical bond formation process.

#### Chemistry Chapter-05: States of Matter

Q1. Calculate the minimum pressure required to compress 500 $$dm^{ 3 }$$of air at 1 bar to 200 $$dm^{ 3 }$$ at $$30^{\circ} C$$ ?

#### Chemistry Chapter-06: Thermodynamics

Q-1: A thermodynamic state function is _______.

1. A quantity which depends upon temperature only.

2. A quantity which determines pressure-volume work.

3. A quantity which is independent of path.

4. A quantity which determines heat changes.

#### Chemistry Chapter-07: Equilibrium

Q.1. At a fixed temperature a liquid is in equilibrium with its vapour in a closed vessel. Suddenly, the volume of the vessel got increased.

I)What will be the final vapour pressure and what will happen when equilibrium is restored finally?

II)Write down, how initially the rates of evaporation and condensation got changed?

III)Write down the effect observed when there was a change in vapour pressure.

#### Chemistry Chapter-08: Redox Reactions

1. Assign oxidation no. to the elements underlined:

(i) $$NaH_2\underline{P}O_4$$

(ii) $$NaH\underline{S}O_{4}$$

(iii) $$H_{4}\underline{P}_{2}O_{7}$$

(iv) $$K_{2}\underline{Mn}O_{4}$$

#### Chemistry Chapter-09: Hydrogen

Q 9.1

Explain on the general basis of electronic configuration – the actual position of hydrogen in periodic table.

#### Chemistry Chapter-10: The s-Block Elements

Q 10.1

Mention the general chemical and physical features of the alkali metals?

#### Chemistry Chapter-11: The p-Block Elements

Q 11.1

Explain the variation pattern in oxidation states of

(i) C to Pb

(ii) B to Tl

#### Chemistry Chapter-12: Organic Chemistry - Some Basic Principles and Techniques

Question 12.1:

Mention the hybridisation states of each carbon atom in the following compounds

CH2=C=O, CH3CH=CH2, (CH3)2CO, CH2=CHCN, C6H6

#### Chemistry Chapter-13: Hydrocarbons

Question 13.1: How do you explain for the generation of ethane through chlorination of methane?

#### Chemistry Chapter-14: Environmental Chemistry

Question 14.1:

What do you mean by environmental chemistry?

#### Maths Chapter-01: Sets

Exercise-1.1

(a). The collection of all day in a week which have the first letter S.

#### Maths Chapter-02: Relations and Functions

Exercise 2.1

Q.1: If $$(\frac{ a }{ 3 } \; + \; 1, \; b \; – \; \frac{ 2 }{ 3 })$$ = $$(\frac{ 5 }{ 3 }, \; \frac{ 1 }{ 3 })$$, what is the value of a and b?

#### Maths Chapter-03: Trigonometric Functions

Exercise 3.1

Q.1: Calculate the radian measurement of the given degree measurement:

(i). $$25\;^{\circ}$$

(ii). $$240\;^{\circ}$$

(iii). $$-47\;^{\circ} \; 30?$$

(iv). $$520\;^{\circ}$$

#### Maths Chapter-04: Principle of Mathematical Induction

Exercise 4.1

Prove the following through principle of mathematical induction for all values of n, where n is a natural number.

1: $$1 + 3 + 3^{2} + …. + 3^{n – 1} = \frac{\left ( 3^{n} – 1 \right )}{2}$$

#### Maths Chapter-05: Complex Numbers and Quadratic Equations

Exercise: 5.1

Q.1: Express the following complex number in x + iy form; $$(4i)\;(-\frac{7}{4}i)$$

#### Maths Chapter-06: Linear Inequalities

Exercise 6.1

Question 1

Solve $$26x < 200$$ when:

(i) The variable(x) is a natural number

(ii) The variable(x) is an integer.

#### Maths Chapter-07: Permutations and Combinations

Exercise- 7.1

Q-1: Form 3- digit numbers by using digits 4, 5, 6, 7 and 8 and assume that

(i) The digits can be repeated.

(ii) Digits can’t be repeated in the 3- digit number.

#### Maths Chapter-08: Binomial Theorem

Binomial Theorem:

[a + b]n = [ nC0 × an ] + [ nC1 × (an – 1) × b ] + [ nC2 × (a n – 2) × b2 ] + [ nC3 × (an – 3 )× b3 ] + . . . . . . . . . . . . . + [ nCn – 1 × a × (bn – 1) ] + [ nCn × bn ]

#### Maths Chapter-09: Sequences and Series

Exercise 9.1

Q1: as = s (s + 3) is the sth term of a sequence. Find the starting five terms of the sequence.

#### Maths Chapter-10: Straight Lines

Exercise – 10.1

Q-1. Construct a quadrilateral in the Cartesian plane with vertices (-2, 5), (0, 6), (4, -4) and (-3, -1). Also, find the area of the quadrilateral.

#### Maths Chapter-11: Conic Sections

Exercise 11.1

Q.1: A circle is given with centre (0, 3) and radius 3. Obtain the equation of the given circle.

#### Maths Chapter-12: Introduction to Three Dimensional Geometry

Exercise 12.1

For any given point, the sign of its coordinates determines the octant in which it will lie.

#### Maths Chapter-13: Limits and Derivatives

Exercise 13.1

Q1.

Evaluate $$\lim_{x \rightarrow 3} x + 5$$ limit:

#### Maths Chapter-14: Mathematical Reasoning

Exercise 14.1

Q.1: State whether the following sentences are statements or not, and justify your answers.

(a) A month has 35 days.

(b) Mathematics is very tough

#### Maths Chapter-15: Statistics

Exercise 15.1

Q1. Calculate the mean deviation about the mean for the given data

5, 8, 9, 10, 11, 13, 14, 18

#### Maths Chapter-16: Probability

Exercise 16.1

Question 1

Write the sample space when a coin is tossed thrice.

#### Physics Chapter-01: Physical World

Q 1. Albert Einstein proposed some of the most important statements on the way science works. What was Einstein trying to say when he stated, “The most incomprehensible thing about the world is that it is comprehensible”?

#### Physics Chapter-02: Units and Measurements

Question 1: Complete the following:

(1) A cube whose sides measure 2 cm each has a volume equal to ________

#### Physics Chapter-03: Motion in a Straight Line

Q1. Among the following cases of motion, in which cases can we consider the body to be approximately a point object:

( a ) A train carriage going from one stations to another.

( b ) A cap on a man’s head who is biking on a circular race track.

#### Physics Chapter-04: Motion in a Plane

Q-1: State whether the following physical quantities are scalar or vector.

(i) Mass

(ii) Volume

(iii) Speed

(iv) Acceleration

#### Physics Chapter-05: Laws of Motion

Q1.What is the direction and magnitude of the net force working on

( a ) a hovercraft moving at a constant speed of 20 km/h on a rough road,

( b ) a bottle cap of mass 5 gm floating on wine,

#### Physics Chapter-06: Work, Energy and Power

Que.1. It is important to understand the sign of work done by a force on a body. Find whether the following are positive or negative:

(a) The work done in lifting of a bucket by the use of a rope.

(b) The work done by the force due to gravity in lifting the bucket.

(c) The work done on the body by friction which is sliding in a plane which is inclined.

#### Physics Chapter-07: System of Particles and Rotational Motion

Q1. Where is the center of mass of the following structures located ( a ) ring , ( b ) cube, ( c ) sphere , and ( d ) cylinder. Is it necessary for a body’s center of mass to lie inside it ?

#### Physics Chapter-08: Gravitation

Q.1: (a). By putting an electric charge inside a hollow conductor you can shield it from the influences of electrical forces. Can a body be shielded from the gravitational influences of nearby matter in a similar fashion?

(b). An astronaut in a shuttle orbiting Mars cannot feel gravity. If he was traveling in a very large space ship would he have detected gravity?

#### Physics Chapter-09: Mechanical Properties Of Solids

Q1. A steel wire of cross-sectional area 3 x 10– 5m2 and length of 5m stretches by the same length as a copper wire of cross-sectional area 4.0 x 10-5m2 and length 4m under a given load. Find the ratio of Young’s modulus of copper to that of steel?

#### Physics Chapter-10: Mechanical Properties of Fluids

Q.1: Explain the following:
(i). Humans have a greater blood pressure in their feet than in the head
(ii). Even though the atmosphere extends over 100 km from the sea level. Atmospheric pressure at an altitude of about 6 km is almost half of its value at sea level.
(iii). Pressure is force divided by area but still, hydrostatic pressure falls into a scalar quantity.

#### Physics Chapter-11: Thermal Properties of Matter

Q.1: The triple points of carbon dioxide and neon are 216.55 K and 24.5K respectively. State

these temperatures on the scales of Fahrenheit and Celsius.

#### Physics Chapter-12: Thermodynamics

Q.1: Water flowing at the rate of 4.0 litres/ minute is heated from 28 °C to 76 °C by a gas burner, if its heat of combustion is 4.0 × 104 J/g. Find the rate of consumption of fuel.

#### Physics Chapter-13: Kinetic Theory of Gases

Q.1: Calculate the ratio of molecular volume to the actual volume of oxygen gas at standard temperature and pressure. (Diameter of oxygen molecule = 3Å)

#### Physics Chapter-14: Oscillations

Q1. Which of the following is periodic motions:
(a) A swimmer making to and fro laps in a river.
(b) A star revolving around a black hole.
(c) A bullet fired from a gun.
(d) A freely suspended bar magnet is moved away from its N –S direction and released.

#### Physics Chapter-15: Waves

Q1. A 5 kg string is under 400 newton of tension. The string is stretched to 40.0 m. If one end of the string is given a transverse jerk, find the amount of time taken by the disturbance take to reach the other end?