P2 Living For The Future

Question 1

Revise how photocells work in revision guide

Answer 1

Pg. 13

Question 2

How does passive solar heating work

Answer 2

Sunlight comes through the window and its radiation is absorbed by the objects inside, this then slowly releases em heat over time and glass reflects radiation back inside the building

Question 3

What are the advantages And disadvantages of wind turbines

Answer 3

Renewable source of energy and doesn’t pollute, however doesn’t work without wind, can be noisy and spoils views

Question 4

Why does the national grid step up the voltage to 400,000V when transporting electricity

Answer 4

Leads to: reduced energy loss, reduced distribution costs, cheaper electricity for customers.

Question 5

Why does the transformer increase the voltage and lower the current

Answer 5

Because a higher current means that the wire gets hotter so there is an increase in resistance

Question 6

What is ionisation

Answer 6

The loss or gain of electrons

Question 7

What are the properties of alpha radiation

Answer 7

Causes the most ionisation, has a short range and is easily absorbed by a sheet of card

Question 8

What are the properties of beta radiation

Answer 8

Has a range of about 1 m, is absorbed by a few millimetres of aluminium

Question 9

What are the properties of gamma radiation

Answer 9

More penetrating, a few cm of lead stops it, but some can also pass through several metres of lead or concrete

Question 10

What must be taken into account when identifying the type of radiation

Answer 10

Background radiation

Question 11

What are the uses of radioactivity

Answer 11

Smoke alarms, thickness in a paper rolling mill, sterilising medical equipment, tracking of blood and to detect blockages in pipes

Question 12

How do we deal with nuclear waste

Answer 12

Low level radioactive waste can be buried in landfill sites, high level is encased in glass deep underground or reprocessed

Question 13

What are the dangers of radioactive waste

Answer 13

Remains radioactive for thousands of years, stored where it can’t leak into water supplies, terrorists could get it and contaminate water supplies

Question 14

Advantages and disadvantages of nuclear power

Answer 14

Fossil fuel not used, greenhouse gases aren’t released, but t very high maintenance and decommissioning costs, risk of accidents

Question 15

What are the properties of a black hole

Answer 15

Cannot see a black hole as light can’t escape form it, such is the size of its gravitational force, where large stars used to be, large mass small size

Question 16

How does centripetal force work on moons with planets with stars

Answer 16

Acts towards the centre of the circular orbit, gravitational attraction is the source of the centripetal force

Question 17

What needs to be specialised about a space suit

Answer 17

Dark visor stopping astronauts being blinded, pressurised suit with oxygen in it, can survive up to 120degrees, but also -160 degrees

Question 18

Advantages and disadvantages of unmanned spacecraft

Answer 18

Costs less, doesn’t out astronauts lives at risk, but have to be reliable as they can’t be fixed up in space alone

Question 19

What’s the difference between asteroids and planets

Answer 19

Asteroids have a low mass, and a planets gravitational force prevents it joining together with another planet

Question 20

What are some beliefs as to how moon was formed and what evidence is there to back this up

Answer 20

2 planets collided, the iron core of the other planet joined with our core core, then the less dense rocks began to orbit and they joined to form our moon. The evidence is that the moon has a lower density than earth, there is no iron on the moon, the moon has the exact same oxygen composition as earth

Question 21

What would happen if a NEO collided with earth

Answer 21

It would end life on Earth, to avoid this we could send a rocket up, altering its course to hopefully miss earth

Question 22

What is red shift

Answer 22

When a source of light is moving away form an observer, it’s wavelength appears to increase which shifts light towards the red end of the spectrum. When scientists look at the sun there is a pattern of lines across the spectrum, however when they look at
Isn’t from different stars the pattern is the same however it is closer to the red end of the spectrum, suggesting that it is older

Question 23

How are stars formed

Answer 23

Nebula clouds are pulled together by gravity, over millions of years the core becomes hot enough for nuclear fusion to take place. Hydrogen joins together to form hellium nuclei and energy is released, the star will shine until this burns out

Question 24

Revise the end of a stars life

Answer 24

Pg. 20

Question 25

What are the advantages of photocells

Answer 25

Don’t need much maintenance, don’t need fuel, don’t cause pollution, a renewable energy, however doesn’t produce energy when it is dark