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Science Flashcards

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German Verbs flashcards
1
Q

What is variation?

A

the differences that occur between different species and within the same species

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2
Q

What is variation caused by?

A

genetics and the environment

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3
Q

What are inherited variations?

A

these are inherited characteristics from parents e.g. facial features, height, hair colour, eye colour

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4
Q

What are environmental variations?

A

traits that are influenced by the environment e.g. hair length, language, strength

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5
Q

Do you think skin colour is an inherited or environmental characteristic?

A

Both - a child will have similar skin colour to its parents, but it can change with sun exposure

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6
Q

What are the 4 features that are truly inherited (and not affected by the environment)?

A

natural eye colour
natural hair colour
blood group
inherited disease

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7
Q

Most features are caused by both inherited and environmental factors, true or false?

A

True

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8
Q

What is continuous variation?

A

a feature that can take on any value in a range e.g. height can be anything from the smallest human possible to the tallest human possible

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9
Q

What is discontinuous variation?

A

a feature that can only have certain values e.g. eye colour can only be brown. blue or green. Another example is blood type

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10
Q

True or false - identical twins are genetically identical

A

True - identical twins come from a single egg and sperm

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11
Q

Do non-identical twins come from the same egg?

A

No - they come from 2 separate eggs fertilized by different sperm

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12
Q

What makes organisms different from each other?

A

DNA - DNA is unique to that organism. Except for identical twins, they have identical DNA

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13
Q

Where is DNA located?

A

at the nucleus of cells and they are tightly coiled into packages called chromosomes

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14
Q

What is a gene?

A

a particular section of DNA

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15
Q

How many chromosomes do humans have?

A

most human body cells contain 46 chromosomes - they are matched up as 23 pairs

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16
Q

Who do people inherit chromosomes from?

A

half from mother, half from father

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17
Q

What does a gene control?

A

separate characteristics e.g. eye colour

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18
Q

What do proteins do?

A

they perform many roles in the body

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19
Q

What type of protein forms cells and tissues?

A

Structural protein

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20
Q

What type of protein carries out reactions in the body?

A

functional proteins

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21
Q

Give 2 examples of structural proteins

A

collagen (found in many human tissues)
cellulose (found in plant cells)

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22
Q

Give an example of a functional protein

A

Enzymes

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23
Q

What do enzymes do?

A

they catalyze (cause) reactions

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24
Q

We may look similar to our parents, but our characteristics will not be exactly the same. Why?

A
  • Because when sex cells are produced (gametes), genes are swapped between the chromosomes so that they are not the same as the parent cell
  • At fertilisation, any sperm could fuse with the egg, mixing the genes from both parents
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25
Q

We may look similar to our parents, but our characteristics will not be exactly the same. What is this called?

A

genetic variation

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26
Q

What is another cause of genetic variation?

A

mutation

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27
Q

What is a mutation?

A

where there is a change in the type or amount of DNA

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28
Q

When do mutations occur?

A
  • When DNA is not copied correctly during replication
  • when chromosome pairs divide unequally during cell division
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29
Q

Give some examples of mutations that can be caused by environmental factors

A
  • radiation, such as UV radiation
  • exposure to certain chemicals
    (these factors are called mutagens)
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30
Q

Is body mass (your weight) determined by genes or the environment?

A

both - it is inherited but is also affected by how much you eat and exercise

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31
Q

What must occur for a woman to become pregnant?

A

fertilisation

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32
Q

What is fertilisation?

A

The fusing of an egg and a sperm cell. The sperm’s nucleus will join the egg’s nucleus

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33
Q

How often do females produce an egg?

A

approximately every 28 days

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34
Q

What is ovulation?

A

When a female produces an egg (every 28 days)

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35
Q

How often do males produce sperm in the testes?

A

continually

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36
Q

What are the 5 stages of fertilisation?

A

1 - ovulation (egg is released from the ovary)
2 - sperm is released into the vagina and travels to the oviduct
3 - the nucleus of a sperm and egg fuse together to produce a zygote
4 - the fertilised egg travels to the uterus and embeds itself into the lining
5 - the fertilised egg is now called an embryo - the lining of the uterus develops into the placenta for nourishing the embryo into a fetus

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37
Q

What is the name given to a male gamete?

A

Sperm

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38
Q

Where does the female egg cell implant after fertilisation?

A

Uterus lining

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39
Q

True or false - there is no mixing of maternal and fetal blood in the placenta

A

True

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40
Q

Where does fertilisation occur?

A

In the Oviduct

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41
Q

True or False - egg cells have a tail?

A

False

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42
Q

What is the name given to a female gamete?

A

Egg cell

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43
Q

Which substance can diffuse across the placenta from mother to fetus?

A

Glucose

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44
Q

What is a zygote?

A

A fertilised egg cell before it has divided into an embryo

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45
Q

What is the placenta?

A

an organ that grows into the wall of the uterus and is joined to the fetus by an umbilical cord

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46
Q

What does the placenta do?

A

allows the exchange of oxygen and nutrients (such as glucose) between the fetus and mother and removes waste such as carbon dioxide and urea

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47
Q

How does the placenta exchange materials between the fetus and mother?

A

by diffusion

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48
Q

What are the 2 functions of the ovaries?

A
  • contain eggs
  • make female hormones which affect the way the body develops and regulates menstrual cycle
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49
Q

How long does it take for a fetus to develop and what is this time called?

A

40 weeks, gestation period

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50
Q

What happens during birth?

A

the cervix relaxes and the muscles in the wall of the uterus contract. Waves of muscle contractions push the baby out of the vagina

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51
Q

which part of the female reproductive system is immediately above the vagina?

A

the cervix

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52
Q

Which part of the male reproductive system holds the testes?

A

the scrotum

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53
Q

Which terms describes the time between pregnancy and birth?

A

Gestation

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54
Q

When an egg cell joins a sperm this is called..

A

fertilisation

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55
Q

A fertilised egg divides to form a ball of cells called…

A

An embryo

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56
Q

Which substances does not move through the placenta to the fetus:
- nutrients
- oxygen
- carbon dioxide

A

Carbon dioxide

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57
Q

What is the role of the testes?

A

they produce sperm and the hormone testosterone

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58
Q

Which tube carries urine out of the body in the male and female reproductive systems?

A

the urethra

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59
Q

What is photosynthesis?

A

Plants make their own food using photosynthesis. They do this by producing glucose and oxygen from carbon dioxide and water

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60
Q

What is the word equation for photosynthesis?

A

Carbon dioxide + Water (then chlorophyll absorbs light) = Glucose + Oxygen

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61
Q

What type of reaction is photosynthesis?

A

Endothermic

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62
Q

What is chlorophyll?

A

the green chemical inside the chloroplasts of plant cells

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63
Q

What does chlorophyll do and where is it located?

A

It is in the leaves and it absorbs light

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64
Q

How does carbon dioxide enter the plant for photosynthesis?

A

carbon dioxide comes from the air and it enters the leaves through the stomata

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65
Q

How does water enter the plant?

A

Through the roots

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66
Q

What happens to the oxygen and glucose made during photosynthesis?

A

the plant releases oxygen into the air, glucose is used to make cell walls and makes the plant grow

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67
Q

What does a plant need for photosynthesis to happen?

A
  • Water
  • Carbon dioxide
  • light
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68
Q

How does light affect photosynthesis?

A

Without enough light, a plant cannot photosynthesise very quickly - even if there is plenty of water and carbon dioxide

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69
Q

What is selective breeding in plants?

A

An artificial process in which humans choose the characteristics to grow e.g. for crops

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70
Q

How does selective breeding happen?

A

Humans choose the best plants to breed together to produce the next crop, they repeat this process over many generations to get the desired plant (can also be done for cattle to produce the best meat)

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71
Q

What types of plants do humans choose for selective breeding?

A
  • disease resistant crops
  • wheat plants that produce lots of grain
  • large or unusual flowers
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72
Q

What types of animals do humans choose for selective breeding?

A
  • animals that produce lots of milk or meat
  • chickens that lay large eggs
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73
Q

What are the benefits of selective breeding?

A

can produce more or better quality food

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74
Q

What are the risks of selective breeding?

A
  • reduced genetic variation which can lead to specific problems e.g. can lead to attack by insects (for plants), or in animals it can create physical problems like deafness or bad hips in dogs
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75
Q

What is a pH scale?

A

Used to measure acidity and alkalinity

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76
Q

What can chemicals be classified as in a pH scale?

A

Acid
Neutral
Alkaline

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77
Q

What does an acid form when it is neutralised?

A

a salt

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78
Q

What are pH indicators?

A

They are substances that change colour when they are added to acidic or alkaline solutions

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79
Q

What type of solution has a pH scale of less than 7?

A

Acidic

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80
Q

What type of solution has a pH of 7?

A

Neutral

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81
Q

What type of solution has a pH scale greater than 7?

A

Alkaline

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82
Q

What colour does a universal indicator change to for a strong acid?

A

Red

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83
Q

What colour does a universal indicator change to for a weak acid?

A

Yellow or orange

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84
Q

What colour does a universal indicator change to for a neutral solution?

A

green

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85
Q

What colour does a universal indicator change to for a strong alkaline?

A

dark blue

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86
Q

What colour does a universal indicator change to for a weak alkaline?

A

light blue

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87
Q

When an acid is dissolved in water what does it produce?

A

Hydrogen ions (protons)

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88
Q

When alkalis are dissolved in water what do they produce?

A

hydroxide ions

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89
Q

What is a base?

A

chemical opposite of an acid

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90
Q

What happens when an acid is mixed with an alkaline

A

a neutralisation reaction occurs to form water

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91
Q

Which of the following could have a pH of 12?:
- Sodium Chloride
- Sulfuric acid
- Sodium Hydroxide

A

Sodium Hydroxide

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92
Q

What is neutralisation?

A

when an acid reacts with a base or alkali to form salt and water

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93
Q

What is rust?

A

when a metal object (like Iron) is exposed to open air and bad weather it corrodes

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94
Q

What causes rust?

A

Air
Moisture
Salt water

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95
Q

How can rust be prevented?

A

Can stop air and water reaching the metal by:
- painting it
- greasing it
- covering it in a more reactive metal e.g. with zinc (galvanise)
- covering it in a less reactive metal e.g. gold, silver (electroplating)

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96
Q

What are the indicators that a chemical reaction has taken place?

A
  • a change of colour
  • a change of temperature
  • the production of a gas or solid (effervescence / precipitation)
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97
Q

What affects the rate (speed) of a chemical reaction?

A
  • temperature
  • concentration
  • particle size
  • presence of a catalyst
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98
Q

What is a chemical reaction?

A

When one or more substances change and produce one or more new chemical substances

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99
Q

What are the substances that are changed by a chemical reaction called?

A

Reactants

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100
Q

What are the substances that are produced by a chemical reaction called?

A

products

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101
Q

A colour change might take place when two substances react. It can also happen when a compound is broken down by heating it. What is this called?

A

Thermal decomposition

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102
Q

Effervescence is an indicator that a chemical reaction has taken place. How does this show in a liquid?

A

Bubbles of gas in the liquid

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103
Q

In an exothermic reaction the reactants hold more energy than the products, so exothermic reactions release energy in the form of heat. How do we know if an exothermic reaction has taken place?

A

there is an increase in temperature

104
Q

Endothermic reactions take in heat. How do we know if an endothermic reaction has taken place?

A

decrease in temperature

105
Q

Chemical reactions always form new substances. True or False?

A

True

106
Q

Different chemical reactions occur at different rates or speeds. Some are very slow, like a car rusting, while others are very fast like a sudden explosion. What 4 factors affect the rate (speed) of a chemical reaction?

A
  • temperature
  • concentration
  • particle size
  • use of a catalyst
107
Q

What is a catalyst?

A
  • something that speeds up a reaction
  • is not changed after the reaction has finished
108
Q

When a substance burns, it reacts with oxygen in the air. What is this known as?

A

Combustion

109
Q

All combustion reactions are exothermic. True or False?

A

True - they release heat

110
Q

What is a displacement reaction?

A

When a more reactive metal displaces a less reactive metal from its compound

111
Q

What is a reactivity series?

A

a list of metals from the most reactive at the top to the least reactive at the bottom

112
Q

What can a reactivity series be used for?

A

to predict displacement reactions

113
Q

Can a displacement reaction take place if there is no difference between the reactivity between 2 metals?

A

No -

114
Q

Aluminium is more reactive than iron. This means the aluminium takes the oxygen from the iron oxide to produce what?

A

Aluminium oxide

115
Q

Iron is dipped into a copper sulfate solution. The products are iron sulfate and copper. Is iron or copper the more reactive metal?

A

This shows that iron is the more reactive metal.

116
Q

When displacement reactions occur, the temperature rises. The larger the temperature rise, the higher the metal is in the reactivity series. True or False?

A

True

117
Q

Which metal would not be included in an experiment using copper sulfate solution to determine a reactivity series?
- Copper
- Aluminium
- Zinc

A

Copper - because they have to be different metals to be able to react

118
Q

What is a chemical change?

A

When a chemical reaction occurs and a new chemical element or compound is formed

119
Q

What is a physical change?

A

when a substance changes its physical state e.g. from a solid to a liquid

120
Q

What is the difference between a chemical and physical change?

A

A physical change does not lead to a new chemical substance forming

121
Q

Which state of matter has particles that are tightly packed in a regular arrangement?
- Gas
- Liquid
- solid

A

Solid

122
Q

Which state of matter has particles with the highest energy?
- Gas
- Liquid
- Solid

A

Gas

123
Q

Which term is used for the change of state from solid to liquid?
- Boiling
- Freezing
- Melting

A

Melting

124
Q

What happens during sublimation?
- a solid turns to a liquid
- a liquid turns to a gas
- a solid turns to a gas

A

A solid turns to a gas

125
Q

Which states of matter can be compressed?

  • Gas only
  • Gas and liquid
  • Liquid only
A

Gas only

126
Q

Which state of matter has particles that are furthest apart?
- Gas
- Liquid
- Solid

A

Gas

127
Q

What happens to the energy of gas particles when they condense to a liquid?

  • The particles gain energy
  • The particles lose energy
  • The particles have the same energy
A

The particles lose energy

128
Q

Why are solids difficult to compress?

  • The particles are very large
  • The particles have high energy
  • The particles are very close together
A

The particles are very close together

129
Q

Why do some collisions between particles not lead to a reaction? - Higher

  • The particles have too little energy
  • The particles have too much energy
  • The particles are strongly attracted to each other
A

The particles have too little energy

130
Q

What elements are placed on the left-hand side of the periodic table?

A

Metals

131
Q

What elements are placed on the right-hand side of the periodic table?

A

Non-metals

132
Q

What are the typical properties of metals?

A
  • shiny
  • high melting points
  • good conductors of electricity
  • good conductors of heat
  • high density
  • malleable and ductile (can change its shape without breaking)
133
Q

Metals and non-metals can react with oxygen to make compounds called what?

A

Oxides

134
Q

Metal oxides are bases. What does this mean?

A

That they can neutralise an acid

135
Q

Non-metal oxides dissolve in water to make acidic solutions. True or False?

A

True

136
Q

Compounds are substances made of two or more types of atoms chemically bonded together. All oxides are compounds, and contain a single element bonded with oxygen. What compound does Magnesium and Oxygen make?

A

Magnesium Oxide

137
Q

What does the ‘mon’ in Carbon Monoxide mean?

A

that it has 1 oxygen atom

138
Q

What does the ‘di’ in Carbon Dioxide mean?

A

that is has 2 oxygen atoms

139
Q

What does the ‘tri’ in Sulfur Trioxide mean?

A

That it has 3 oxygen atoms

140
Q

Silicon has the symbol Si. What is the formula of silicon dioxide?

A

SiO2

141
Q

When magnesium is heated with a Bunsen burner it forms magnesium oxide. Where do the oxygen atoms come from?

A

the air

142
Q

Metal oxides are solids. One of the properties of metal oxides is that they act as bases. What does this mean?

A

that they are able to neutralise acids, producing a salt plus water.

143
Q

Some metal oxides dissolve in water to make an alkali, a solution which has a pH higher than 7. Alkalis also neutralise acids to produce a salt plus water. True or False?

A

True

144
Q

What is seen when magnesium burns in air?

A

A white flame

145
Q

Acids react with most metals. What are the products when an acid reacts with a metal?

A

Salt and Hydrogen

146
Q

What is the word equation for when a metal reacts with an acid?

A

Metal + Acid = Salt + Hydrogen

147
Q

What would the pH of an acidic solution be?

A

pH below 7

148
Q

What pH do acids which react with metals usually have?

A

pH less than 3

149
Q

What is seen when a metal reacts with an acid?

A
  • the metal getting smaller
  • bubbles being produced
150
Q

The name of the salt formed from the reaction of a metal and acid can be worked out using the names of the metal and the acid.

Name of metal + name of acid → salt name

What salt would be formed between Magnesium and Nitric Acid?

A

Magnesium nitrate

151
Q

What salt would be formed between Calcium and Hydrochloric acid?

A

Calcium Chloride

152
Q

Name 3 types of acid

A

Hydrochloric acid
Nitric acid
Sulfuric acid

153
Q

What is the name of the salt formed when iron reacts with sulfuric acid?

A

Iron Sulfate

154
Q

What salts would be formed from the reaction between Zinc and the following acids?:
Hydrochloric acid
Nitric acid
Sulfuric acid

A

1 - Zinc chloride
2 - Zinc nitrate
3 - Zinc sulfate

155
Q

What type of salts are made from the reaction of sulfuric acid?

A

Sulfate

156
Q

Nitrate salts are made from the reaction of which acid?

A

Nitric acid

157
Q

What would we see if a sample of silver, gold or platinum is placed in acid? (think about where these metals are in the reactivity series)

A

No reaction

158
Q

What would we see if a sample of potassium or sodium is placed in acid? (think about where these metals are in the reactivity series)

A

violent reaction

159
Q

What are circuit diagrams used for?

A

to show how electrical components are connected in a circuit

160
Q

What are Ammeters used for?

A

to measure the current flowing through components

161
Q

What are Voltmeters used for?

A

To measure the potential difference across components

162
Q

Which component provides power to a circuit?

A

A cell, battery or power supply

163
Q

What unit is the current or flow of charge measured in?

A

Amps

164
Q

An electrical current in a wire is a flow of what?

A

electrons

165
Q

How are components, like motors, lamps and cells, represented in a circuit diagram?

A

circuit symbols represent each component

166
Q

What is the difference between a battery and a cell?

A

A battery is made by connecting 2 or more cells together

167
Q

What are the units of measurement of current?

A

Amperes (or Amps)

168
Q

What are the units of measurement of potential difference?

A

Volts

169
Q

What is used to measure current?

A

An ammeter

170
Q

What is used to measure potential difference?

A

Voltmeter

171
Q

How is an ammeter connected into a circuit?

A

In series, anywhere in the circuit

172
Q

How is a voltmeter connected into a circuit?

A

in parallel with one lead on each side of the component

173
Q

What is a series circuit?

A

when the components are all connected to the same loop

174
Q

What is a parallel circuit?

A

when a component is on its own separate branch of the circuit e.g. a voltmeter

175
Q

What is a sound wave?

A

a vibration that travels through a solid, liquid or gas such as the air or water

176
Q

What type of sound has a large amplitude?

A

a loud sound

177
Q

What type of sound has a high frequency?

A

a high pitched sound

178
Q

How are sounds analysed?

A

Using waves traces

179
Q

How are sounds made?

A

all sounds are made by something shaking or vibrating e.g. guitar string or drum

180
Q

How does sound travel?

A

The air particles start vibrating and push on the air particles next to them, so the vibrations are passed on.

181
Q

If you pluck a stretched rubber band hard, it makes a loud sound. If you pluck it gently, it makes a quiet sound. What does the loudness depend on?

A

how big the vibration of the air is

182
Q

What type of wave is a sound wave?

A

A longitudinal wave

183
Q

What is the lowest frequency a human can hear ?

A

20Hz

184
Q

What is the highest frequency humans can hear ?

A

20,000 Hz

185
Q

What scale are sound levels measured on?

A

Decibels (dB)

186
Q

Too much noise can damage hearing. Exposure to 90 decibel sound levels for a long time can cause permanent hearing loss. Exposure to a brief sound level of 140 decibels will cause pain and can cause permanent damage to hearing. What is the typical decibel for background noise at home?

A

40dB

187
Q

What is the typical decibel for whispering?

A

20dB

188
Q

What is the typical decibel for normal talking?

A

60dB

189
Q

Light travels as a _______ wave and can be reflected by surfaces and objects

A

transverse

190
Q

What type of reflections do smooth shiny surfaces produce?

A

specular reflections

191
Q

What type of reflections do rough surfaces produce?

A

diffuse reflections

192
Q

What is a Ray diagram used for?

A

shows that path of a light ray being reflected from a plane mirror

193
Q

What is the ray of light travelling towards the mirror called?

A

the incident ray

194
Q

What is the ray of light travelling away from the mirror called?

A

the reflected ray

195
Q

What is the dashed line called on a Ray diagram?

A

the normal - it is drawn 90 degrees to the surface of the mirror

196
Q

What is the angle of incidence on a Ray diagram?

A

The angle between the normal, and the incident ray

197
Q

What is the angle of reflection on a Ray diagram?

A

the angle between the normal, and the reflected ray

198
Q

The angle the ray is reflected is always the same as the angle the light hits the mirror. True or False?

A

True

199
Q

What happens to parallel light rays during specular reflection?

A

They are all reflected in the same direction

200
Q

Which of these can produce clear images?

A

Specular reflection

201
Q

Which type of diagram is used to show how images are formed by a mirror?

A

a Ray diagram

202
Q

Light is refracted when it enters a material like water or glass. What does this mean?

A

light will reduce in speed as it travels through, causing it to change direction.

203
Q

What can be used to show the path light takes when it is refracted?

A

a Ray diagram

204
Q

The shape of a glass or plastic lens can affect the way it refracts light. True or False?

A

True

205
Q

What does a converging lens do?

A

makes something look much larger

206
Q

What objects use converging lenses?

A

Telescopes and magnifying glasses
- glasses for long sighted people

207
Q

Looking through a glass block magnifies an object. True or false?

A

False - it stays the same like looking out of a window

208
Q

What does a diverging (concave) lens do?

A

makes something look much smaller

209
Q

What objects use diverging lenses?

A

Glasses (for short-sighted people)
Cameras used to take wide images like landscapes

210
Q

What does a fish eye lens do?

A

makes something look spherical. e.g. skyscrapers in a city wouldn’t look straight but would curve into the top of the picture

211
Q

Why does light refract?

A

Its speed changes

212
Q

Which direction would light refract when travelling from air to glass?

A

Towards the normal

213
Q

Which direction would light refract when travelling from air to glass?

A

Away from the normal

214
Q

What is the angle of refraction?

A

The angle between the refracted ray and the normal

215
Q

Does light travel faster in air or in glass?

A

Air

216
Q

Which type of lens can be used to focus light to a point?

A

a convex lens

217
Q

Why are lenses used to produce images?

A

To produce clear, focused images

218
Q

Where would you find a convex lens?

A

In a camera

219
Q

Why does the lens in your eye change shape?

A

To focus objects at different distances

220
Q

What is static electricity?

A

It is a build-up of electrical charge on an object.
i.e. When objects become positively charged or negatively charged, usually because of friction between insulators.

221
Q

What happens when you rub one neutral , electrically insulating object against another?

A

Some of the electrons are transferred across, leaving a negative charge on one of the objects, and a deficit on the other

222
Q

What can static electricity cause?

A
  • an electric shock
  • it can cause objects to levitate, like making your hair stand on end
  • it can cause attraction, like making a balloon stick to a wall
223
Q

What are the 2 types of electrical charge?

A

positive and negative

224
Q

What type of material allows electrical current to flow through it easily?

A

Conductor

225
Q

Which type of material does not allow electrical current to flow through it easily?

A

Insulator

226
Q

Which materials can be charged by friction?

A

Insulators

227
Q

What is the term for an object which contains equal numbers of positive and negative charges?

A

Neutral

228
Q

What type of charge does an electron have?

A

Negative

229
Q

What happens when objects with the same static charge are near to each other?

A

They repel each other (push away from each other)

230
Q

What happens when objects with the opposite static charge are near to each other?

A

They attract

231
Q

Which type of charge can be easily transferred between insulators?

A

Negative

232
Q

What might cause a neutral object to be attracted to a charged object?

A

Polarisation

233
Q

When an atom loses an electron, which type of charge will the remaining ion have?

A

Positive

234
Q

True or false? When current flows through a wire, it generates a magnetic field.

A

True

235
Q

Which of these is NOT an advantage of an electromagnet?
- The strength can be changed
- It is always magnetic
- It can be switched off
- It can be reversed

A

It is always magnetic

236
Q

Which of the following happens to an electromagnet when a soft iron core is added?
- the electromagnet doesn’t change
- The electromagnet reverses
- the electromagnet gets stronger
- the electromagnet gets weaker

A

the electromagnet gets stronger

237
Q

What is the name of the coil of wire with many turns?

A

Solenoid

238
Q

True or false? Motors and loudspeakers use the same effect to work.

A

True

239
Q

In an electrical motor, what will happen if the current direction is reversed?

A

The direction of rotation will reverse

240
Q

In an electrical motor, what will happen if both the flow of current is reversed and the permanent magnet is reversed?

A

Nothing will change

241
Q

Which of these wouldn’t increase the strength of an electromagnet?
- coiling the wire
- adding a plastic core
- adding a soft iron core
- increasing the current

A

adding a plastic core

242
Q

Which part of a loudspeaker causes the air to vibrate?

A

The cone

243
Q

True or false? A microphone works in the same way as a loudspeaker.

A

False

244
Q

How does an electromagnet work?

A

It uses a current to generate a magnetic field

245
Q

What 3 things can strengthen an electromagnet?

A
  • increasing the current
  • increasing the number of turns in the coil
  • adding an iron core
246
Q

What can an electromagnet with a permanent magnet be used to make?

A

motors and loudspeakers

247
Q

Any wire with a current running through it has a magnetic field. True or False?

A

True

248
Q

The magnetic field around a wire with a current running through it are drawn as circles around the wire. What does it mean if the lines of these circles are closer together?

A

the magnetic field is stronger

249
Q

What is a coil of wire with many turns called?

A

A Solenoid

250
Q

What does a typical electromagnet consist of?

A

a wire coiled around an iron core

251
Q

The iron core in an electromagnet is often called a soft iron core. Why?

A

because iron is magnetically soft - this means the iron is easy to magnetise and demagnetise

252
Q

Where are electromagnets used?

A
  • automatic door locks
  • headphones
  • scrap yard cranes
253
Q

Electromagnets can be switched on and off. Why?

A

because they are only magnetic while a current is running through the coil

254
Q

How can you increase the strength of an electromagnet?

A
  • using a longer piece of wire so it has more turns on the coil
  • using a bigger current
  • adding a soft iron core - because iron is a magnetic material
255
Q

In the motor effect, if two magnets of the same pole (e.g. north and north) are brought near to each other what happens?

A

they repel

256
Q

In the motor effect, if two magnets of the opposite pole are brought near to each other (e.g. north and south), what happens?

A

they attract

257
Q

What is the motor effect?

A

if you put a wire coil with a current going through it near a magnet it causes the wire to turn

GERMAN (5 decks)

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