Paper 1 Corrections

Question 1

What is a use of ultrasound?

Answer 1

Pregnancy / foetal scanning
echo location

Question 2

What is a use of infrasound?

Answer 2

studying the Earth’s structure
whale communication

Question 3

Mesuring the counts of two rocks with geiger muller

Answer 3

put rock(s) in front of/near
tube + measure (count rate) separately for the
two different rocks + measure each count for the
same time period
keep source-detector
distance the same for both
rocks
take (into account)/
measure background count
6. repeat readings and take
average(s) (1)

Question 4

what is the force that keeps things in orbit

Answer 4

centripetal

Question 5

what is red shift

Answer 5

Increase wavelength / decreased frequency as a star/object moves away

Question 6

How does red shift provide evidence for the big bang theory

Answer 6

big bang has expanding
universe with galaxies moving away
(from each other) (1)

Question 7

definition of CMBR

Answer 7

radiation that comes from all the
universe

Question 8

How does CMB prove the big bang theory

Answer 8

the Big Bang theory has a beginning / initial
explosion that releases/gives out
radiation (1

Question 9

uses of infrared

Answer 9

short-range communication
cooking

Question 10

uses of microwaves

Answer 10

cooking / communication

Question 11

uses of radiowaves

Answer 11

communication
oscillations in electrical currents

Question 12

Why does white light go boombaya

Answer 12

its a combination of all visible light - the colours have) different wavelengths and different wavelengths / colours travel at different speeds (1)
so refract by different amounts

Question 13

what is a replacement for human stopwatch

Answer 13

electronic timer - eliminates reaction time as a factor

Question 14

on car practical, how do you compensate for friction?

Answer 14

raise one end of the ramp so the car falls due to gravitu

Question 15

Describe nuclear fission plants + how they are moderated

Answer 15

neutrons released in a chain reaction
 slow(er) neutrons needed for fission
 (some) neutrons are too fast
 control rods can be moved in and out
 control rods control speed of the reaction
AO2
 graphite core is the moderator
 graphite core slows down the neutrons
 moveable rods absorb neutrons
 moveable rods make more or fewer neutrons available for
fission

Question 16

what are the backround sources of radiation?

Answer 16

cosmic (rays) /
Sun
rocks /
ground/
nuclear/waste (1)
(nuclear) power stations (1)
plant (sources) (1)
buildings (1)

food (1)
water (1)
medical (1)

Question 17

how are radiowaves produced?

Answer 17

Produced intentionally by humans

Emitted by oscillating (free) electrons or alternating current (AC)

Generated in electrical circuits or aerials

Question 18

how are gamma rays produced?

Answer 18

Produced spontaneously or randomly

Emitted from the nucleus during energy changes or rearrangement

Result from radioactive decay, nuclear fission or fusion, or annihilation (e.g. PET scanning)

Help stabilise the nucleus

Question 19

what is the evidence for the expanison of the universe?

Answer 19

Red shift of light from distant galaxies/stars

Light is shifted to the red side of the electromagnetic spectrum

Observed wavelength is longer → source is moving away

Nearly all galaxies show red shift

Universe is expanding at an increasing rate (linked to dark energy

Question 20

What is the evidence that the universe began at a single point?

Answer 20

CMBR

Question 21

uses of radioactive substances

Answer 21

smoke alarm (1)
food irradiation (1)
sterilising (1)
detecting leaks/cracks (1)
gauging thicknesses (1)
in medicine diagnostic (

Question 22

how are control rods used in a generator

Answer 22

they shut the reactor down when nessasary

Question 23

how are moderators used in a generator

Answer 23

they slow down neutrons to enable a chain reaction to take place

Question 24

nuclear fission chain reaction

Answer 24

a neutron collides with/fired at auranium nucleus (1)
releasing (2/3) extra neutron(s) (1)
which go on to collide with more
nuclei (1)

Question 25

Nebula -> main sequence star

Answer 25

nebula as a cloud of gas/dust (1) gas / atoms pulled together / towards each other (1) by gravitational force (1) temperature increase (1) hot enough for nuclear fusion (1)

Question 26

gamma rays damage body

Answer 26

Gamma rays can damage cells They are ionising, meaning they have high frequency and very high energy can cause cancer

Question 27

Flashcard 1: What are the arguments for using nuclear power?

Answer 27

Fossil fuels are running out → nuclear can replace them No carbon emissions → does not contribute to global warming Low running costs → economically competitive With reprocessing, fuel can last hundreds of years High power output compared to wind or solar

Question 28

Flashcard 2: What are the arguments against using nuclear power?

Answer 28

Expensive to build and decommission → less economical than other options Risk of nuclear disasters → potential loss of life and environmental contamination Toxic nuclear waste lasts a long time Waste storage issues → risk of groundwater contamination Security risks → potential for terrorism or use in bomb making

Question 29

Flashcard: How do seismic waves provide evidence about the structure of the Earth?

Answer 29

Seismometers detect seismic waves from earthquakes Seismic waves are refracted as they travel through Earth → shows different densities Two types of seismic waves: P-waves (longitudinal): can travel through solids and liquids S-waves (transverse): can travel through solids only, not liquids The S-wave shadow zone shows part of Earth's interior must be liquid (outer core) P-waves can pass through the liquid core, but are refracted

Question 30

Flashcard 1: What is nuclear fission and what are its pros and cons?

Answer 30

Definition: A heavy nucleus splits when hit by a neutron Produces 2 daughter nuclei, more neutrons, and energy Can cause a chain reaction Advantages: Already in use for energy production Disadvantages: Produces radioactive waste Difficult to dispose of waste Risk of accidents

Question 31

Flashcard 2: What is nuclear fusion and what are its pros and cons?

Answer 31

Definition: Light nuclei join together Requires very high energy, temperature, pressure, and particle density Releases helium and energy Advantages: No harmful waste products Disadvantages: Not yet achieved on a practical scale Hard to reach required conditions (high energy/temperature/pressure)