ohms law, dc circuits and kirchoffs laws

Question 1

what happens to opposite charges

Answer 1

attract

Question 2

what happens to like charges

Answer 2

repel

Question 3

what is resistance

Answer 3

Resistance opposes the flow of electric current in a circuit.

It is measured in Ohms (Ω) and is denoted by the symbol ‘R.’

Question 4

equation for ohms law

Answer 4

V = IR

Question 5

Definition of ohms law

Answer 5

​The current and potential difference through an ohmic conductor held under constant physical conditions are directly proportional, with the constant of proportionality being resistance.

Question 6

what is direct current

Answer 6

In a direct current, the flow of electrons is consistently in one direction around the circuit.

Question 7

what is alternating current

Answer 7

In an alternating current, the direction of electron flow continually reverses.

Question 8

how to measure current

Answer 8

using an ammeter, must be in series with component

Question 9

what does the current through a component depend on?

Answer 9

The current through a component depends on both the resistance of the
Component and the potential difference across the component.

Question 10

how to measure potential difference

Answer 10

using a voltmeter places in parallel with component

Question 11

do conductors have low resistance or high resistance

Answer 11

low

Question 12

do insulators have low resistance or high resistance?

Answer 12

high

Question 13

what is the conductivity of an ohmic conductor

Answer 13

Ohmic conductors exhibit a linear relationship between the electric field (voltage) applied across them and the resulting current.

Question 14

what is the conductivity of a semi conductor?

Answer 14

Semiconductors exhibit a non-linear relationship between voltage and current.

Question 15

factors affecting semiconductors conductivity

Answer 15

temperature, impurities, and external conditions

Question 16

what is the relationship between pd and current for a fixed resistor

Answer 16

For a fixed resistor, the potential difference is directly proportional to the current.

Question 17

what will happen if you double the amount of energy into the resistor

Answer 17

Doubling the amount of energy into the resistor results in a current twice as fast running through the resistor.

Question 18

example of ohmic conductor

Answer 18

resistor

Question 19

what is a filament bulb

Answer 19

A filament bulb, also known as an incandescent bulb, is a type of electric light bulb that produces light by heating a wire filament until it emits visible light

Question 20

what happens when an electric current passes through the filament

Answer 20

it heats up due to its resistance to the flow of electricity.

Question 21

what happens to current in a filament bulb?

Answer 21

In a filament bulb, the current does not increase as fast as the potential difference.

Question 22

what happens if you put more energy in a bulb

Answer 22

The more energy that is put into the bulb, the harder it is for the current to flow - the resistance of the bulb increases.

Question 23

what happens if the p.d in a Bulb increases

Answer 23

As the potential difference increases, so does the temperature of the thin wire inside the bulb, the filament.

Question 24

what does high temperature do in a bulb

Answer 24

The higher temperature increases the vibrations of the ions in the filament, which makes it harder for the electrons to get past.

Question 25

what is a semi conductor diode

Answer 25

A semiconductor diode only allows current to flow in one direction.

Question 26

what will happen if p.d tries to push current the wrong way in a diode

Answer 26

If the potential difference is arranged to try and push the current the wrong way (also called reverse-bias) no current will flow as the diode’s resistance remains very large.

Question 27

when will Current only flow in a diode

Answer 27

Current will only flow if the diode is forward-biased.

Question 28

relationship between resistance and p.d in a diode

Answer 28

The diode’s resistance is very large at low potential differences but at higher potential differences, the resistance quickly drops and current begins to flow.

inversely proportional

Question 29

what is resistivity

Answer 29

Resistivity is a fundamental property of materials that describes how strongly a specific material opposes the flow of electric current

Question 30

unit for resistivity

Answer 30

ohm metres

Question 31

what is resistivity dependent on?

Answer 31

Resistivity is an fundamental property of a material and is independent of its shape and size.

Question 32

equation for resistivity

Answer 32

P = RA/ L
P = resitivity
R - resistance
A - cross sectional area
L - length

Question 33

equation to calculate power loss in cable

Answer 33

P = I^2 x R

Question 34

what does a circuit consist of

Answer 34

voltage/current source
connecting wires
elements like resistors, capacitors, inductors, transistors, diodes

Question 35

what is a series circuit

Answer 35

If all the elements of a circuit are arranged in such a way that the magnitude of current that flows through each element is equal to the total current in the circuit, then the circuit is said to be a series circuit.

Question 36

properties of a series circuit

Answer 36

The same amount of current flows through each element.

The voltage drop across each element is not the same.

The total resistance of the circuit is the sum of the resistance of all the resistors.

If one of the elements fails, then the current will stop flowing in the whole circuit.

Question 37

what are parallel circuits

Answer 37

If the elements of a circuit are arranged in such a way that the magnitude of the current that flows through each element is not equal to the magnitude of the total current in the circuit, then the circuit is said to be a parallel circuit.

Question 38

what is voltage drop

Answer 38

Voltage drop refers to the reduction in voltage that occurs as electrical current flows through a conductor
(such as a wire or a circuit)

It is a natural phenomenon that happens due to the inherent electrical resistance of the conductor.

Question 39

properties of a parallel circuit

Answer 39

The total current gets divided in different proportions in all the branches of the circuit. The proportion of current in each branch is given by the ‘current divider rule’.

The voltage drop across all the parallel elements is same.

Question 40

what happens if any on element fails in a parallel circuit

Answer 40

If any one element fails, the current stops flowing only in that particular branch of the circuit where the faulty element exists.

Question 41

what happens if an element in a series circuit stops working

Answer 41

: In a series circuit if ant element stops working, then it breaks the entire circuit