Physics - P2

Question 1

What do scientists believe started the universe and what evidence is there for it?

Answer 1

• scientists believe that the universe started with the Big Bang and the evidence for it is red shift

Question 2

What does passive solar heating use glass for?

Answer 2

• to keep buildings warm

Question 3

What are the advantages of photocells?

Answer 3

• they do not new fuel or cables

- they only need little maintenance and cause no pollution

Question 4

How does a wind turbine cause electricity?

Answer 4

• kinetic energy from the moving air turns the blades on a wind turbine to produce electricity

Question 5

What increases global warming?

Answer 5

• some gases in the earths atmosphere trap heat from the sun increasing global warming

Question 6

How does a dynamo produce electricity?

Answer 6

• when a coil of wire rotates inside a magnetic field

Question 7

What does the size of currents depend on?

Answer 7

• the number of turns
• the strength of the field
• the speed of rotation

Question 8

What do transformers in an electricity generator do?

Answer 8

• change the size of the voltage and current

Question 9

What does the national grid do?

Answer 9

• transmits electricity around the country at high voltage and low current
• this reduces energy loss

Question 10

What are nuclear fuels?

Answer 10

• radioactive

Question 11

What can radiation cause?

Answer 11

• cancer

Question 12

What remain radioactive for a long time?

Answer 12

• waste products

Question 13

In power stations, what do fuels release?

Answer 13

• energy as heat

Question 14

In power stations, why is water heated?

Answer 14

• to produce steam

Question 15

What do turbines do?

Answer 15

• turn generators

Question 16

What do generators produce?

Answer 16

• electricity

Question 17

Why is the efficiency equation and what do you do to the answer to dos the percentage?

Answer 17

• efficiency = energy output / energy input

- you times the answer by 100

Question 18

What are the main forms of ionising radiation?

Answer 18

• alpha
• beta
• gamma

Question 19

What do alpha, beta and gamma uses depend on?

Answer 19

• their penetrative and ionisation properties

Question 20

What orbits the sun in our solar system?

Answer 20

• planets, asteroids and comets

Question 21

What keep bodies in orbit?

Answer 21

• centripetal forces

Question 22

What are medium sized stars formed by and what will they eventually become?

Answer 22

• they are formed from nebulae and will eventually become red giants, white dwarfs and finally black dwarfs

Question 23

What may happen when two planets collide?

Answer 23

• a new planet and a moon may be formed

Question 24

What is the universe explored by?

Answer 24

• telescopes on the earth and in space

Question 25

What do large distances mean?

Answer 25

• this means that it takes a long time for information to be received and inter-galactic travel unlikely

Question 26

What would an asteroid strike cause?

Answer 26

• climate change

- species existence