feb mocks

Question 1

what are the two equations for acceleration?

Answer 1

a = (v-u)/t
v squared = u squared x 2as

Question 2

what is friction?

Answer 2

a force that opposes motion

Question 3

what is the relationship between force, mass, and acceleration?

Answer 3

F=ma

Question 4

what is the relation ship between weight, mass, and gravitational field strength?

Answer 4

w=mg

Question 5

what are the factors affecting stopping time?

Answer 5

speed, mass, road condition, tyre condition, and reaction time

Question 6

what is elastic behaviour?

Answer 6

the ability of a material to recover its original shape after the forces causing deformation have been removed

Question 7

how does insulation protect the device/user?

Answer 7

the copper wires are wrapped in an insulating material so it doesn’t come into contact with the user

Question 8

how does double insulation protect the user and device?

Answer 8

• only for metal cases
• a layer of insulation is put around the case to prevent the person being electrocuted

Question 9

how does earthing protect the user and device?

Answer 9

• if the live wire touches the metal casing it can become electrified and could electrocute the user
• the earth wire provides a low resistance path to the earth
• there is a surge in current in the earth wire and so also in the live wire
• so the fuse melts and breaks the circuit

Question 10

how do fuses protect the user and device?

Answer 10

melts if the current is too high, has to be replaced

Question 11

how do circuit breakers protect the user and device?

Answer 11

• automatic electromagnets
• same job as fuse but can be reset and reused
• works faster than fuses

Question 12

what is the relationship between power current and voltage?

Answer 12

P=IV

Question 13

what is the relationship between energy transferred, current, voltage and time?

Answer 13

E=IVt

Question 14

what is ac?

Answer 14

current constantly changes direction, supplied by mains electricity

Question 15

what is dc?

Answer 15

current always flows in the same direction, supplied by cells or batteries

Question 16

what are the advantages of a parallel circuit?

Answer 16

• components can be switched on/off independently
• circuit still works if one breaks
• bulbs have similar brightness

Question 17

what are the advantages of a series circuit?

Answer 17

• less wires
• less power
• cheaper
• easier to assemble

Question 18

how is the current in a series circuit affected by the number of components?

Answer 18

more things in circuit = less current overall

Question 19

how does resistance in a LDR vary with illumination?

Answer 19

more illumination = less resistance

Question 20

how does a thermistor vary with temperature?

Answer 20

temp increases = resistance decreases

Question 21

what is current?

Answer 21

the rate of flow of charge

Question 22

what is electric current in solid metallic conductors?

Answer 22

negatively charged electrons

Question 23

what is voltage?

Answer 23

energy transferred per unit time

Question 24

what is a volt?

Answer 24

joule per coulomb

Question 25

can all waves be reflected and refracted?

Answer 25

yes

Question 26

what are the uses of radiowaves?

Answer 26

broadcasting and communications

Question 27

what are the uses of microwaves?

Answer 27

cooking and satellite transmissions

Question 28

what are the uses of infrared?

Answer 28

heaters and night vision

Question 29

what are the uses of visible light?

Answer 29

optical fibres and photography

Question 30

what is the use for ultraviolet?

Answer 30

fluorescent lamps

Question 31

what are the uses of xrays?

Answer 31

observing internal structure of objects

Question 32

what are the uses of gamma rays?

Answer 32

sterilising foods and medical equipment

Question 33

what are the dangers of microwaves?

Answer 33

internal heating of body tissue

Question 34

what are the dangers of infrared?

Answer 34

skin burns

Question 35

what are the dangers of ultraviolet?

Answer 35

damage to surface cells and blindness

Question 36

what are the dangers of gamma rays?

Answer 36

cancer, mutations of cells

Question 37

what kind of waves are light waves?

Answer 37

transverse

Question 38

what kind of waves are sound waves?

Answer 38

longitudinal

Question 39

what is specific heat capacity?

Answer 39

the energy required to change the temperature of an object by one degrees celcius per kg of mass

Question 40

what is the thumb in flhr?

Answer 40

force

Question 41

what is the index finger in flhr?

Answer 41

magnetic field

Question 42

what is the middle finger in flhr?

Answer 42

current

Question 43

what is the nature of alpha?

Answer 43

2 neutrons, 2 protons

Question 44

what is the nature of beta?

Answer 44

one electron

Question 45

what is the nature of gamma?

Answer 45

em wave

Question 46

what is irradiation?

Answer 46

when an object is exposed to radiation

Question 47

what is the role of control rods?

Answer 47

absorb neutrons and completely remove them from the fission process, helps adjust rate of nuclear fission in reactor

Question 48

what are control rods made of?

Answer 48

boron or cadmium

Question 49

what is the role of moderators?

Answer 49

slow down/absorb the KE of neutrons

Question 50

what are moderators made of?

Answer 50

graphite

Question 51

what is the shielding of a nuclear reactor made of?

Answer 51

the vessel is made of steel then surrounded by a thick layer of concrete