Electrical circuits

Question 1

How does a material become charged?

Answer 1

A material becomes negatively charged by gaining electrons and becomes positively charged by losing electrons.

Question 2

What will two objects carrying the same type of charge do if they are brought close to each other?

Answer 2

They will repel each other.

Question 3

What is an electric field?

Answer 3

A region of space around a charged object in which another charged object will experience an electrostatic force.

Question 4

What happens to the strength of an electric field as you get further from the charged object?

Answer 4

It decreases.

Question 5

What is electric current?

Answer 5

Rate of flow of charge.

Question 6

What units are charge, current, and time measured in?

Answer 6

Coulombs (C), amperes (A), seconds (s) respectively.

Question 7

What is the same at all points when charge flows in a closed loop?

Answer 7

Current.

Question 8

What must there be in a closed circuit so that electrical charge can flow?

Answer 8

Source of potential difference (p.d.).

Question 9

Which two factors does current depend on and what are their units?

Answer 9

Resistance in ohms (Ω), p.d. in volts (V).

Question 10

What happens to the current if the resistance is increased but the p.d. stays the same?

Answer 10

Current decreases.

Question 11

What is an ohmic conductor?

Answer 11

A conductor where current is directly proportional to the voltage so resistance is constant (at constant temperature).

Question 12

What happens to the resistance of a filament lamp as its temperature increases?

Answer 12

Resistance increases.

Question 13

What happens to the resistance of a thermistor as its temperature increases?

Answer 13

Resistance decreases.

Question 14

What happens to the resistance of a light-dependent resistor when light intensity increases?

Answer 14

Resistance decreases.

Question 15

What are the main features of a series circuit?

Answer 15

Same current through each component, total p.d. of power supply is shared between components, total resistance of all components is the sum of the resistance of each component.

Question 16

What are the main features of a parallel circuit?

Answer 16

p.d. across each branch is the same, total current through circuit is the sum of the currents in each branch - total resistance of all resistors is less than the resistance of the smallest individual resistor.

Question 17

Electrical current def

Answer 17

Where charge flows round a circuit (carried by electrons) and measured In amps

Question 18

What is electrical current the flow of

Answer 18

CHARGE

Question 19

What do electrical field lines show

Answer 19

The direction of the force that a small positive charge would experience when placed in the electrical field

Question 20

Electrostatic force defenition

Answer 20

Two charged objects exerting a non contact force on each other

Question 21

Is air resistance a contact or non contact force

Answer 21

Contact

Question 22

Is electro static force a contact or non contact force

Answer 22

Non contact

Question 23

What is a spark

Answer 23

A flow of electrons between two strongly charged objects

Question 24

Which was does current flow in circuit diagrams

Answer 24

Positive->negative (the conventional current)

Question 25

What is the relation between total resistance between two or more components and the smallest resistance of any branch in parallel?

Answer 25

The total resistance of two or more components is always less than the smallest resistance of any branch because another route(loop) Means more current can flow, even though p.d. has not changed

Question 26

P.d. In series vs parrallel

Answer 26

Series-in series the total potential difference is the sum of the individual potential difference across each component Parrallel-in parallel the potential difference across each component is the same and equal to the source voltage

Question 27

Potential difference(voltage) defenition

Answer 27

the measure of the energy transferred per unit of charge between two points in a circuit

Question 28

What Is the p.d. Across a component

Answer 28

The work done on it by each co log of charge that passes through it(Same for power supplies and batteries)

Question 29

Current in series vs parrallel

Answer 29

Series-in series, the current is the same throughout all components Parrallel-in parallel, the current splits and flows through different branches

Question 30

What does adding more resistance in parallel do to the total resistance?

Answer 30

The total resistance decreases

Question 31

Resistance in series vs parrallel

Answer 31

Series-in series total resistance increases as more resistors are added Parrallel-in parallel, total resistance decreases with each added resistor