Series and parallel circuits

(In Grade 8) What is the conventional current direction?

From positive to negative (+ to negative)

(In real life) What is the electron flow direction?

From negative to positive (negitive to +)

What is a series circuit?

Series: one pathway for current to flow

How are components arranged in a series circuit?

One after the other (in series)

What happens to the current in a series circuit?

Current is constant throughout the circuit

What is the effect of adding resistors to a series circuit?

Total current decreases

What is the effect of adding cells to a series circuit?

Total current increases, Bulbs glow brighter

What happens when you add bulbs in a series circuit?

Total resistance increases → current decreases → bulbs glow dimmer

What is a parallel circuit?

Parallel: multiple pathways for current to flow

How does current behave in a parallel circuit?

Current is not constant in the circuit, Current is shared across the loops

What happens when you add resistors?

Adding resistors = increases total current

What is the effect of adding cells?

Adding cells does NOT affect current

Bulb's brightness remains the same

Does bulb brightness change when adding more bulbs?

Bulbs' glow remains the same

What changes are noted when adding bulbs?

Increases resistors, Increases current, Decreases resistances

What does a cell convert?

Converts chemical potential energy to electrical energy

What is an ammeter used for?

Measures electric current in amperes

What does a light bulb convert electrical energy into?

Converts electrical energy to heat and energy

What does a light emission diode (LED) do?

Converts electrical energy into light energy

What is a photocell?

A special LED that absorbs light and converts it to electrical energy

Give examples of devices that use photocells.

Solar panel, Some calculators

What energy conversion does a door bell perform?

Converts electrical energy into sound energy

What is direct current (DC)?

Current in which charges flow in one direction only. Example: batteries

What is alternating current (AC)?

Current that periodically reverses direction. Example: household mains supply

What is the main difference between DC and AC?

DC: flows in one direction. AC: reverses direction repeatedly

What type of current do modern battery

operated doorbells use?

What happens when the switch is closed in a DC doorbell circuit?

DC flows, turning the electromagnet in the speaker on

What happens when the switch is released in a DC doorbell circuit?

The electromagnet turns off

Why does a DC doorbell produce a 'ding dong' sound?

Because the electromagnet turns on then off, producing the distinct 'ding dong' sound

What is 'alternating current'?

Current that periodically changes direction.

What happens when the switch is closed in a doorbell circuit?

Current flows; alternating current creates a magnetic field that attracts the clapper.

Why does the clapper release frequently in AC powered bells?

Because the magnetic field changes direction with the alternating current.

What component in older doorbells causes the vibration?

An electromagnet that repeatedly attracts and releases the clapper.

What distinct sound results from the rapid attraction and release in AC bells?

A repeated 'Krrrr' noise caused by the clapper's rapid movement.

What happens between like charges?

Like charges repel

What happens between unlike charges?

Unlike charges attract

What is the electric force?

The electric force is the attraction or repulsion between charged objects

Which factors determine the strength of the electric force?

Magnitude of the charges, Distance between the charges

What is Coulomb's Law?

The law that quantifies the electric force between charges based on charge sizes and distance

What is static electricity?

The build up of electric charges on an object

What happens when you rub a balloon on hair?

Electrons transfer from hair to balloon

After rubbing a balloon on hair, what charge does the hair have?

Positive (due to electron loss)

After rubbing a balloon on hair, what charge does the balloon have?

Negative (due to electron gain)

What is an electric discharge?

A sudden and brief flow of electrons

What happens to charges that build up on an object?

They eventually move off the object

Give an everyday small

scale example of electric discharge.

What does Ohm's Law describe?

Ohm's Law: Electric current is directly proportional to the voltage causing it to flow.