STATIC ELECTRICITY

1. Causes:

Friction

Results in "stationary" electricity

2. Charge:

Neutral object: Equal positive and negative charges

Positive charge: Shortage of electrons

Negative charge: Excess of electrons

3. Explanation of Charge:

When materials are rubbed, electrons move, leading to one material gaining a negative charge and the other gaining a positive charge.

4. Forces between Charges:

Like charges repel, opposite charges attract.

5. Polarisation:

A charged object near a neutral one causes charges in the neutral object to separate, resulting in a positive and negative side while the object remains neutral as a whole.

ELECTRICAL CURRENT

1. Components for Flow:

Source of energy

Closed circuit

Conductors

2. Electrical Current:

Continuous flow of charge (electrons)

3. Circuit Interruption:

Open circuit possibilities:

Loose contact at switch

Loose connection

Broken wire or filament

4. Battery:

Combination of cells in series, providing electrical energy (chemical energy → electrical energy)

5. Resistor:

Offers resistance to current flow

Larger resistance leads to smaller current

6. Fuse:

Device with low melting point interrupts current if too large, protecting electrical apparatus and preventing fires

EFFECTS OF ELECTRICAL CURRENT

1. Heating Effect:

Applications: light bulbs, stoves, kettles, heaters, irons, etc.

2. Magnetic Effect:

Applications: electromagnets, speakers, electric drills, vacuum cleaners, electric doorbells

Increased by connecting more cells in series, increasing windings around the nail, placing an iron nail in the coil, or using a hard steel nail instead.

3. Chemical Effect:

Electrolysis breaks down chemical compounds into simpler materials, converting electrical energy to chemical energy.

CURRENT ELECTRICITY

1. Direction:

Conventional current flows from positive to negative pole of the cell or battery.

2. Series Circuits:

Only one path for flow of charge

More cells in series increase total current, making light bulbs glow brighter

Blown light bulb breaks circuit, others won't glow

3. Parallel Circuits:

Multiple paths for flow of charge

More cells in parallel keep total current the same

Blown light bulb doesn't break circuit, others still glow

OUTPUT AND INPUT DEVICES

1. LED (Light Emission Diode):

Converts electrical energy to light energy

Used in doorbells, remote controls, etc.

2. Photocell:

Absorbs light, producing electrical power

Used in calculators, doorbells, etc.

3. Doorbell or Buzzer:

Functions via an electromagnet vibrating at 60 Hz, converting electrical energy to magnetic, motion, and sound energy.