p1 Energy

Question 1

What is conduction?

Answer 1

when heat moves from one object to another object through direct touch

Question 2

What is dissipated energy?

Answer 2

Energy that is transferred to the environment so that it can no longer be usefully transferred

Question 3

What is efficiency?

Answer 3

How much energy is usefully transferred by an appliance

Question 4

What is energy transfer?

Answer 4

When energy is moved from one energy store to another

Question 5

What is the gravitational field strength?

Answer 5

The pull of the force of gravity on each kg of mass.

Question 6

What is insulation?

Answer 6

A material that reduced energy transfers to or from a system

Question 7

What is kinetic energy?

Answer 7

The energy stored in an object that is moving

Question 8

What is a lubricant?

Answer 8

A substance added to surfaces to reduce the amount of friction (oil)

Question 9

What is a non renewable source?

Answer 9

A resource that is not replaced as it is used

Question 10

What is power?

Answer 10

The rate at which energy is transferred or the rate at which work is done

Question 11

What is a renewable resource?

Answer 11

A resource that is replenished as it is used

Question 12

What is specific heat capacity?

Answer 12

The amount of energy needed to raise the temperature of 1kg of a material by 1 degrees celsius

Question 13

What is watt?

Answer 13

A unit of power
1 watt= 1 joule transferred per sec

Question 14

What is work done,

Answer 14

The energy transferred when a force moves

Question 15

Where are electric fields found?

Answer 15

Around all charged objects

Question 16

What two characteristics affect the strength of the field?

Answer 16

-The closer u get the stronger the field
- the closer the lines the stronger the field

Question 17

Describe the electric field around a positively charged sphere

Answer 17

• Field lines travel from positive to negative
• further away= weaker the field because field lines move further apart

Question 18

What do field lines always go from?

Answer 18

Positive to negative

Question 19

Explain sparking in terms of electric fields. (5 marks)

Answer 19

• high pd causes a strong electric field
• electrons in the air particles are removed (ionisation)
• ionised air can conduct
• current flows through it
• this is the spark

Question 20

What is ionisation?

Answer 20

When an atom or molecule either loses or gains electrons which makes it charged.

Question 21

If an atom or molecule gains electrons does it become positively charged or negatively charged?

Answer 21

Negatively charged= anion

Question 22

If an atom or molecule loses electrons does it become positively charged or negatively charged?- WHATS the scientific word

Answer 22

Positively charged= cation

Question 23

What is specific heat capacity?

Answer 23

The amount of energy needed to change the temperature of 1kg of a substance by 1 degrees Celsius

Question 24

The specific heat capacity equation tells us that the temperature change of a substance depends on three things. Name them.

Answer 24

• mass of a substance (m)
• energy supplied
• specific heat capacity of the substance

Question 25

What is the equation for specific heat capacity?

Answer 25

Energy= mass* specific heat capacity* temp change

Question 26

In an IV graph experiment, what happens to the resistance of the filament lamp?

Answer 26

Resistance increases due to increased collisions between metal ions and delocalised electrons

Question 27

What happens to the thermal store of the ions in a filament lamp?

Answer 27

Increases

Question 28

What happens to the current when the potential difference is negative in the diode version of the IV graph experiment?

Answer 28

Almost no current flows

Question 29

Describe the relationship between the potential difference and the current in the filament lamp?

Answer 29

As the pd increase the current increases BY A SMALLER AMOUNT

Question 30

Describe the relationship of the resistance and the current in the filament lamp?

Answer 30

Resistance= increases Current = decreases

Question 31

What allows the current to flow in one direction in a diode?

Answer 31

Low resistance when potential difference is positive

Question 32

What is the equipment used for the experiment on characteristics of pd and current of components (5)

Answer 32

- battery - wires -ammeter -voltmeter - variable resistor

Question 33

Describe the steps in investigating the current and pd characteristics of components.

Answer 33

1- use voltmeter to read the pd across resistor 2- use an ammeter to read the current through the resistor 3- record values in a table 4- adjust variable resistor and record both new readings 5- do this several times to get range of readings 6- switch direction of battery (pd reversed) + voltmeter and ammeter= negative values 7- continue taking several readings 8- plot graph of current against pd

Question 34

What is an error that can be caused during the experiment of the fixed resistor?

Answer 34

If resistor too hot= temp increases instead of staying constant= graph will not be directly proportional

Question 35

For the filament lamp, how would u continue the experiment?

Answer 35

1- replaced resistor with filament lamp 2- adjust variable resistor and read both pd and current 3- do this for a range of values with the battery in the forward and reverse direction

Question 36

For the dioxide how would u continue the experiment?

Answer 36

-replace filament lamp with diode - add an extra resistor (because diodes are very easily damaged by high current) - current is low= we need a sensitive ammeter= milliammeter - adjust the variable resistor a number of times and record the pd and current - do this with the battery in the forward and reverse direction

Question 37

In what case do we get a current in a diode? (Pd)

Answer 37

When the pd is around 0.6-0.7 volts

Question 38

What happens to current if the potential difference increases from 0.6-0.7 volts?

Answer 38

Current rises sharply

Question 39

In an experiment, the diode is shown to have no current, what is the reason behind this and why?

Answer 39

Potential difference is reversed because in the reverse direction a diode has a high resistance

Question 40

What is the relationship between the light intensity and the resistance of an LDR?

Answer 40

Light intensity increases= resistance decreases

Question 41

Describe why an LED night light does not work during the day?

Answer 41

- light intensity is high+ resistance is low - loop with LDR has the lowest resistance - most current flows through the LDR+ NOT LAMP - lamp does not light

Question 42

Explain how an LED night light manages to light at night.

Answer 42

- light intensity is low + resistance is high - loop with lamp has the lowest resistance - most current flows through lamp - lamp lights up

Question 43

What happens to the temps tire as insulation got thicker?

Answer 43

Temperature decreases less over the 20 mins

Question 44

What are the 8 steps in investigating the change of temp from the thickness of insulation?

Answer 44

1- mark a mine on the outside of the beaker around the 200cm cubed mark 2- wrap the beaker in the insulating material 3- use kettle to boil water 4- pour hot water into the beaker up to the marker line 5- use a cardboard with a hole in for the large beaker (hole for thermometer 6- insert thermometer and leave for a minute to record starting temp 7- record temp of water every 5 mins up until 20 mins

Question 45

What are three hazards in the insulation experiment and what are the three risks?

Answer 45

- hot water= scalds - hot beaker= burns - electricity and water= shock