P.1

Rubbing Electric charges P.1

Matter Atom Proton + + Neutron Electron - - P.1

Hydrogen Electrically neutral P.1

Only electron can be added or removed No. of electrons = no. of protons Electrically neutral P.1

Positive charge - - P.1

Negative charge P.1

Like charges repel P.1

Unlike charges attract P.1

Charged object attracts uncharged object P.1

Test P.1

Kinetic energy of electrons Rubbing P.2

Positive charges are formed because of loss of electron Negative charges are formed because of gain of electron Principle of conservation of charge - - P.2

Unit of charge Charge of an electron = - 1.6x C No. of electrons in 1 C = 6.25 x Coulomb (C) P.2 Smallest charge = - 1.6x C

Conductor Insulator Conduct electricity & heat energy Free electrons P.2

Charges repel each other Resultant force = 0 Charges are rest on the surface P.3 Charge distribution

Higher charges density at sharp edge P.3 Charge distribution

Positive charges are formed because of loss of electron Negative charges are formed because of gain of electron Kinetic energy of electrons Rubbing - - P.3

Resistor - - P.3

5 kV

EHT e-e- P.3

EHT e-e- P.3

Electrons are repelled Sphere is neutral Positive & negative charges are formed Charge sharing P.5

Electrons are repelled & flow to the sphere e-e P.5

Negative charges are shared between the rod & the sphere ---- P.5

---- Charge sharing produces same kind of charge Amount of charge decreases after sharing P.5

Electrons are attracted Sphere is neutral Positive & negative charges are formed P.5

Electrons are attracted & flow to the rod e-e- P.5

Positive charges are shared between the rod & the sphere ++++ P.5

++++ Charge sharing produces same kind of charge Amount of charge decreases after sharing P.5

Charges are attracted each other P.5 (e.g.) -4 x C +9 x C

Positive Charges are repelled P.5 (e.g.) Total charges = +5x C

P.5 (e.g.) Charges in each ball = +2.5x C

Electrons are repelled Sphere is neutral Positive & negative charges are formed Charge induction P.4

e-e- e-e- Positive charges are attracted by the negative charges of the rod Negative charges are shared between the sphere & the earth Earthing P.4

Charges are shared by the ball & the Earth P.4 Bigger in size will have more charges Nearly all charges in ball will be gone Earthing

The surface area of the earth is much larger Nearly all the negative charges are lost P.4

Charge induction produces opposite sign of charge Amount of charge remains the same P.4

Electrons are attracted Positive & negative charges are formed Sphere is neutral P.4

e-e- e-e Negative charges are attracted by the positive charges of the rod Positive charges are shared between the sphere & the earth Earthing P.4

The surface area of the earth is much larger Nearly all the positive charges are lost P.4

Charge induction produces opposite sign of charge Amount of charge remains the same P.4

No charge Electrons are repelled Positive & negative charges are formed P.4

The spheres must be separated under the presence of the charged rod P.4

Both kinds of charges are produced P.4

Charged sphere attracts neutral ball P.4

Charge sharing & the ball is repelled Charges are neutralized & the ball becomes uncharged P.4

Hairs are charged by sharing Hairs repel each other since they have the same charge P.4

Initially, hairs are neutral P.4

Initially, hairs are negatively charged P

Charges repel each other P

Neutral smoke grains are attracted by the charged conductor P.4

Light bulb lights up Current flows P.4

Small current flows Light-beam galvanometer P.4

Sparks P.4

Light up bunsen burner P.4

Electric wind + - P.4

+

P.6 (2002) Water is neutral. Attracted by charged ruler Action and Reaction Pair.

P.6 (2001) Can be negative charges because LIKE charges repel X Action and Reaction Pair. X Same F, but different masses. Larger Mass, less displacement

P.7 (0427) 3 +ve charges. Repel each other 3 -ve charges. Repel each other 2 +ve charges and 1 –ve charge. Not for any 2 of them X

P.7 (0427) A (+ve) attracts B (neutral) A (+ve) attracts C (neutral) B (neutral) CANNOT attract C (neutral) X X

P.7 (0427) A (+ve) repels B (+ve charge) A (+ve) attracts C (neutral) B (+ve charge) attracts C (neutral) X X X

P.7 (0427) A (+ve) attracts B (-ve charge) A (+ve) attracts C (neutral) B (-ve charge) attracts C (neutral) X X X

P.7 (0029)

P.7 (9829) + -

P.7 (9727)

P.7

Electric force P.

Attractive electric force P.

P.7

Conductor Attractive force Equal amount of positive & negative charges are induced Attractive force is greater than the repulsive force because of shorter distance Repulsive force Repulsive force P.7

Insulator Equal amount of positive & negative charges are induced in each molecule Attractive force is greater than the repulsive force because of shorter distance Attractive force Repulsive force P.7

Electroscope Test of charges P.7

Opposite signs of charges are induced Gold leaf diverges because of repulsive force P.7

P.8 (9629) Repel each other X Attract each other Can attract neutral object

P.8 (0344) Can attract neutral object True Net negative charge =0 False

Discharge through air + - P

Discharge through air + - P The charged rod will be less negative.

Field Gravitational field m Weight mg Electric field Force acts on an object with some special property +- P.8

Shark detects other fish by the change of electric field in their bodies P.8

Direction of electric field lines Direction of electric force acting on a negative charge is in opposite direction Direction of electric force acting on a positive charge P.9

+ - -

F=0 Neutral point Direction of resultant force Direction of electric field line P.9

+-

The electric field line must be perpendicular to the metal plate otherwise the charge will move P.9

The electric field is uniform between 2 parallel metal surface The charges appear on the inner surface P.9

Field line starts from positive charge Field line end at negative charge + - P.9

Field lines have NO branches or cross each other Resultant force point in one direction only P.9

NO field line exist inside metal P.9

E

Electric field strength Electric force acting on +1C charge + - P.9

P.10 e.g. W=mg = 2 x (10) = 2 x (N) W FeFe F e =W= 2 x (N) + + Q=F e / E =2 x / 1.25 x10 4 =+1.6 x (C)

Draw the electric field pattern P

Draw the electric field pattern P.10

P.10 (0331) + Cancel each other

P.10 (0331) - Cancel each other

Applications of Electrostatics P.10

P.11

P.12

Positively charged drum Neutralized positive charges Carbon powder sticks on positive charges Carbon powder sticks on positively charged paper Infra-red neutralize all the charges

EE P.12

I want to paint my new house !!! I want to paint my new house !!! P.12

Rub / charge the wall Electrostatic spray Electrostatic spray P.12 Less paint required Sticks strongly

Electrostatics Hazards P.13

Sparkles

P.13

Dust Problem ??? P.13

Static charges damage microphone P.13

Anti-static pad P.13

Anti-static tyres P.13

to neutralize the charges in clouds to lead the charges from lightning to the ground

P.14 True False

P.14

Electrons are attracted Positive & negative charges are formed P.14

Electrons are attracted & flow to the rod e-e- P.14

Both of them are positively charged P.14 Charge sharing produces same kind of charge

P.14

No charge Electrons are repelled Positive & negative charges are formed P.14 Charging by Induction

The spheres must be separated under the presence of the charged rod P.14

Both kinds of charges are produced P.14

P

P

P.15

The electric field is uniform between 2 parallel metal surface The charges appear on the inner surface P.15

A B - Ball is negatively chargedBall is attracted to LHS

P.15 A B -

A B - Charge sharing. Ball is +ve. + Ball is attracted to RHS

P.15 A B +

A B Ball is negatively chargedBall is attracted to LHS +-

P.15 W=mg = 9.1 x (10) = 9.1 x (N) W FeFe F e =eE=(1.6 x ) (6 x10 4 ) (N) - F net =F e - W = 9.6 x (N) If d=10 cm =0.1 m =9.6 x (N) a=1.055 x10 16 (m/s 2 ) v 2 = a d v = 45.9 x 10 6 (m/s)