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Three Dimensional Geometry Class 12th Notes - Free NCERT Class 12 Maths Chapter 11 Notes - Download PDF

Three Dimensional Geometry Class 12th Notes - Free NCERT Class 12 Maths Chapter 11 Notes - Download PDF

Edited By Ramraj Saini | Updated on Apr 23, 2022 01:13 PM IST

Notes for Class 12 Maths chapter 11 are regarding Three Dimensional Geometry. In chapter 11 we will be going through the geometric concepts in Three-dimensional geometry Class 12 notes. This Class 12 maths chapter 11 notes contains the following topics: direction cosines, direction ratios, equation of a straight line in vector and cartesian form, Equation of line passing through 2 points, the angle between them, coplanar, collinear and their conditions, equations in vector and cartesian forms, Equation of parallel and perpendicular lines and their distances, intercept form. NCERT class 12th Math chapter 11 notes contain standard formulas and detailed information that are implemented in problems. NCERT Class 12 Math chapter 11 notes and Class 12 Math chapter 12 notes contain a detailed explanation of topics, examples, exercises. The document will help students can cover all the topics that are in NCERT Notes for Class 12 Math chapter 11 textbook. It also contains the frequently asked questions by students which makes to know the concept of the topic. Every concept that is in CBSE Class 12 Maths chapter 11 notes is explained here in a simple way that students can get it easily. All these concepts can be downloaded as pdf from Class 12 Maths chapter 11 notes pdf download, ncert notes for Class 12 Maths chapter 11 are the notes for Three-dimensional geometry, Class 12 Three dimensional geometry notes pdf download.

Also, students can refer,

NCERT Class 12 Chapter 11 Notes

1646385805692

A line OA makes angles α,β,γ with x,y, and z-axis respectively. then cosα, cosβ, cosγ are called direction cosines.

l = cosα, m = cosβ, n = cosγ

1646385840374

1646385941481

Note: Direction cosines are always unique.

Direction ratios: The values that are proportional to directional cosines are called direction ratios.

\\ \text{a,b,c are ratios, then}\ \frac{l}{a}=\frac{m}{b}\ =\frac{n}{c} \\ \\ \text{Direction cosines of ratios a,b,c :} \\ l = \pm \frac{a}{\sqrt{a^2+b^2+c^2}} \\ \\ m = \pm \frac{b}{\sqrt{a^2+b^2+c^2}} \\ \\ n = \pm \frac{c}{\sqrt{a^2+b^2+c^2}} \\ \\

Direction cosines passing through two points:

1646386125857

1646386126143

Direction cosines: 1646386126706

Direction ratios: 1646386126401

NOTE: Directions ratios need not be unique

Equation of Stright Line:

Equation of a Line passing through the Point and parallel to vector b

1646386833619

\\ where,\ \vec{a}\ \text{ is a position vector.}\ \vec{b}\ \text{ is a vector that is parallel to the line}

Cartesian form:

1646386834084

where, 1646387143347 be the point that line passes through and a, b, c are the direction ratios.

l,m,n are the direction cosines, then the equation is:

1646387144319

Equation of line that is passing through 2 points:

Points are : 1646387187040

1646387187358

1646387187641are position vectors.

Cartesian form of two points:

Points are : 1646387238848

1646387269015

Vector equations of 2 lines:

\vec{r_{1}}=\vec{a_{1}}+\lambda \left ( \vec{b_{1}}-\vec{a_{1}} \right ) and\ \vec{r_{2}}=\vec{a_{2}}+\lambda \left ( \vec{b_{2}}-\vec{a_{2}} \right )

The angle between 2 lines:

1646387554602

Cartesian form: Let be an angle between the lines below:

1646387596386

Then,

1646387598149

Direction cosines of1646387597836with angle are:

1646387597201

Few conditions:

when lines are perpendicular,1646387597570

then cartesian form:

1646387598601

when lines are parallel1646387596820

then cartesian form:

\\ \frac{a_1}{a_2}=\frac{b_1}{b_2}=\frac{c_1}{c_2} \\ \\ \frac{l_1}{l_2}=\frac{m_1}{m_2}=\frac{n_1}{n_2}

Shortest path:

Vector equations of 2 lines:

\vec{r_{1}}=\vec{a_{1}}+\lambda \vec{b_{1}}\ and\ \vec{r_{2}}=\vec{a_{2}}+\mu \vec{b_{2}}

Shortest distance

1646388248135

where\ \vec{a_1}, \vec{a_2}\ are\ position\ vectors\ and\ \vec{b_1}, \vec{b_2}\ \text{ are vectors in the direction of a line.}

Cartesian form for two lines:

1646389042586

Cartesian form :

Shortest distance between the lines:

1646389059521

Distance between two Parallel Lines:

Lines are said to be coplanes when they are parallel.

Vector equations of 2 lines:

\vec{r_{1}}=\vec{a_{1}} + \lambda \vec{b_{1}}\ and\ \vec{r_{2}}=\vec{a_{2}}+\mu \vec{b_{2}}

Distance between two Parallel Lines:

1646389838805

Note: If lines are parallel, they always have the same direction ratios.

Distance between two points:1646390198559

1646390198861

The midpoint of two points: 1646390199113

1646390199406

PLANE:

The plane is found unique, only if they satisfy any one of the following:

  • if normal form and distance from the origin are give
  • pass-through point and perpendicular
  • passes through non-collinear points

Equation of plane in normal form:

1646390200905

Cartesian form: one equation of plane is ax + by + cz = d and another equation of plane is lx + my + nz = p

Formula: Foot of perpendicular= (ld, md, nd).

Equation of plane perpendicular to vector and passing through a point:

Vector equation: 1646390200685

Cartesian form: Equation of plane that passes through the point 1646390201516

1646390203508

Equation of plane passing through non-collinear points:

Vector form: 1646390204997

Cartesian form: 1646390199906 are non-collinear points

Equation: 1646390202442

If they are collinear: 1646390207371

Intercept Form:

Let a, b, c be x-intercept, y-intercept, z-intercept, respectively then

Equation of intercept= xa+yb+zc=1

Equation of Plane Passing through the intersection of two Planes:

equation of the planes is

\vec{r_1}.\vec{n_1}=d_1 \ and \ \vec{r_2}.\vec{n_2}=d_2

equation of the plane passing through the intersection :

1646390202105

Cartesian form: equation of planes are 1646390203998

equation of the plane passing through the intersection :

1646390204462

Coplanarity:

\\ Lines:\vec{r_{1}}=\vec{a_{1}}+\lambda \vec{b_{1}}\ and\ \vec{r_{2}}=\vec{a_{2}}+\mu \vec{b_{2}}\ are\ coplanar\ then \\ Vector form: \left ( \vec{a_{1}}-\vec{a_{2}} \right )\cdot \left ( \vec{b_{1}}\times\vec{b_{2}} \right )=0

Cartesian form:

For Two lines

1646390204736 are coplanar then

1646390202973

The angle between Two Planes: θ be the angle between two planes.

1646390200398are normals, the angle between \vec{r_1}.\vec{n_1}=d_1 \ and \ \vec{r_2}.\vec{n_2}=d_2

1646390201824

Cartesian form: planes are 1646390204227,

1646390203775

Angle Between Line and Plane:

Vector form: equation of a line is 1646390203277

angle θ between the line and the normal to the plane is

1646390201207

Cartesian form: a, b and c are direction ratios and lx + my + nz + d = 0 is equation of plane then

1646390205541

With this topic we conclude NCERT class 12 chapter 11 notes.

The link for the NCERT textbook pdf is given below:

URL: ncert.nic.in/ncerts/l/lemh205.pdf

Significance of NCERT Class 12 Maths Chapter 11 Notes:

NCERT Class 12 Maths chapter 11 notes are helpful for students to understand the topics well. In Three Dimensional Geometry Class 12 chapter 10 notes we have discussed many topics: direction cosines, direction ratios, equation of a straight line in vector and cartesian form, Equation of line passing through 2 points, angle between them, coplanar, collinear and their conditions, equations in vector and cartesian forms, Equation of parallel and perpendicular lines and their distances, intercept form. NCERT Class 12 Mathematics chapter 12 is also very useful and covers major topics of Class 12 CBSE Mathematics Syllabus.

The CBSE Class 12 Maths chapter 12 will help to understand the formulas, statements, and topics. There are also most frequently asked questions along with topic wise explanations. By referring to the document, gives the knowledge on all the topics of Class 12 chapter 11 Three Dimensional Geometry pdf download.

NCERT Class 12 Notes Chapter Wise.

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Subject wise NCERT solutions

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Frequently Asked Question (FAQs)

1. What is the importance of Three-dimensional geometry Class 12 notes?

It helps you, students, to score good marks in very little time as notes contain all the important and key points that are most important to be memorized for their good grades.

2. Who is the father of NCERT notes Class 12 Maths Chapter 11 Three Dimensional Geometry?

Euclid of Alexandria is the father of Three-dimensional geometry.

3. What is the importance of Three Dimensional Geometry Class 12 notes?

Generally 3 dimensional contains 3 dimensions: x,y, and z.

So to locate an object or anything in a 3-dimensional plane we need the topic Three Dimensional Geometry. They are used to find the exact location of a point.

4. Can you pictorially show 3-dimensional space?

Generally 3 dimensional contains 3 dimensions: x,y, and z.

So to locate an object or anything in a 3-dimensional plane we need the topic Three Dimensional Geometry. They are used to find the exact location of a point.

5. Examples of 3-dimensional bodies? Are they solid shapes?

3 dimensional shapes: cone,cube,cuboid,cylinder,prism etc. Yes, 3-dimensional shapes are always solid shapes.

Articles

Get answers from students and experts

A block of mass 0.50 kg is moving with a speed of 2.00 ms-1 on a smooth surface. It strikes another mass of 1.00 kg and then they move together as a single body. The energy loss during the collision is

Option 1)

0.34\; J

Option 2)

0.16\; J

Option 3)

1.00\; J

Option 4)

0.67\; J

A person trying to lose weight by burning fat lifts a mass of 10 kg upto a height of 1 m 1000 times.  Assume that the potential energy lost each time he lowers the mass is dissipated.  How much fat will he use up considering the work done only when the weight is lifted up ?  Fat supplies 3.8×107 J of energy per kg which is converted to mechanical energy with a 20% efficiency rate.  Take g = 9.8 ms−2 :

Option 1)

2.45×10−3 kg

Option 2)

 6.45×10−3 kg

Option 3)

 9.89×10−3 kg

Option 4)

12.89×10−3 kg

 

An athlete in the olympic games covers a distance of 100 m in 10 s. His kinetic energy can be estimated to be in the range

Option 1)

2,000 \; J - 5,000\; J

Option 2)

200 \, \, J - 500 \, \, J

Option 3)

2\times 10^{5}J-3\times 10^{5}J

Option 4)

20,000 \, \, J - 50,000 \, \, J

A particle is projected at 600   to the horizontal with a kinetic energy K. The kinetic energy at the highest point

Option 1)

K/2\,

Option 2)

\; K\;

Option 3)

zero\;

Option 4)

K/4

In the reaction,

2Al_{(s)}+6HCL_{(aq)}\rightarrow 2Al^{3+}\, _{(aq)}+6Cl^{-}\, _{(aq)}+3H_{2(g)}

Option 1)

11.2\, L\, H_{2(g)}  at STP  is produced for every mole HCL_{(aq)}  consumed

Option 2)

6L\, HCl_{(aq)}  is consumed for ever 3L\, H_{2(g)}      produced

Option 3)

33.6 L\, H_{2(g)} is produced regardless of temperature and pressure for every mole Al that reacts

Option 4)

67.2\, L\, H_{2(g)} at STP is produced for every mole Al that reacts .

How many moles of magnesium phosphate, Mg_{3}(PO_{4})_{2} will contain 0.25 mole of oxygen atoms?

Option 1)

0.02

Option 2)

3.125 × 10-2

Option 3)

1.25 × 10-2

Option 4)

2.5 × 10-2

If we consider that 1/6, in place of 1/12, mass of carbon atom is taken to be the relative atomic mass unit, the mass of one mole of a substance will

Option 1)

decrease twice

Option 2)

increase two fold

Option 3)

remain unchanged

Option 4)

be a function of the molecular mass of the substance.

With increase of temperature, which of these changes?

Option 1)

Molality

Option 2)

Weight fraction of solute

Option 3)

Fraction of solute present in water

Option 4)

Mole fraction.

Number of atoms in 558.5 gram Fe (at. wt.of Fe = 55.85 g mol-1) is

Option 1)

twice that in 60 g carbon

Option 2)

6.023 × 1022

Option 3)

half that in 8 g He

Option 4)

558.5 × 6.023 × 1023

A pulley of radius 2 m is rotated about its axis by a force F = (20t - 5t2) newton (where t is measured in seconds) applied tangentially. If the moment of inertia of the pulley about its axis of rotation is 10 kg m2 , the number of rotations made by the pulley before its direction of motion if reversed, is

Option 1)

less than 3

Option 2)

more than 3 but less than 6

Option 3)

more than 6 but less than 9

Option 4)

more than 9

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