Prelim Revision

Question 1

Spontaneous nuclear fission

Answer 1

A large atomic nucleus splits into two nuclei of smaller mass number plus several free neutrons, releasing energy.

Question 2

Stimulated nuclear fission

Answer 2

A large atomic nucleus is induced by bombarding it with neutrons, it splits into two nuclei of smaller mass number plus several free neutrons, releasing energy.

Question 3

Nuclear fusion

Answer 3

In nuclear fusion, two small atomic nuclei combine to form a larger nucleus, releasing energy.

Question 4

CMBR

Answer 4

As the universe expanded it has cooled but we should be able to find some heat energy remaining.

Question 5

Vertical velocity…

Answer 5

Is always -9.8

Question 6

Weight acting down a slope:

Answer 6

Fparallel=mgsinθ

Question 7

Weight acting normal to slope:

Answer 7

Fperpendicular=mgcosθ

Question 8

Random uncertainty:

Answer 8

max value – min value/number of values

Question 9

Impulse

Answer 9

The sudden force acting on an object for a short interval of time.
As time of contact increases, the impulse decreases.
Change in momentum.
Can be calculated using area under Ft graph.

Question 10

How to find displacement

Answer 10

Area under velocity time graph

Question 11

Horizontal velocity

Answer 11

Vh=vcosθ

Question 12

Vertical velocity

Answer 12

Vv=vsinθ

Question 13

Conservation of energy

Answer 13

v=√2gh

Question 14

Momentum when stick

Answer 14

m1u1+m2u2=mv

Question 15

Momentum when no stick

Answer 15

m1u1+m2u2=m1v1+m2v2

Question 16

Impulse

Answer 16

The time of contact during a collision.
A short time of contact means a larger force.

Can find impulse using the area under the Ft graph.

Question 17

Change in momentum

Answer 17

(∆ P)
∆P=mv-mu
Ft=∆P

Question 18

Inelastic collision:

Answer 18

When KINETIC energy is not conserved.

Calculate total kinetic energy before and after.

Question 19

Elastic collision:

Answer 19

When KINETIC energy is conserved.

Calculate total kinetic energy before and after.

Question 20

Stellar objects radiation

Answer 20

Emit more radiation the hotter they are.

Emit radiation over a wide range of frequencies.

Question 21

Momentum eqn

Answer 21

P=mv

Question 22

t=1/Ho

Question 23

Dark matter

Answer 23

Undetectable matter believed to be responsible for gravity.

Question 24

Dark energy

Answer 24

Causes the expansion of the universe to accelerte.

Question 25

What is beta decay evidence for?

Answer 25

Neutrinos

Question 26

Quarks

Answer 26

up,charm,top +2/3
down,strange,bottom -1/3

Question 27

Leptons

Answer 27

Electron,muon,tau -1
Corresponding neutrino 0

Question 28

Antiparticles

Answer 28

All particles have them.
Same mass, different charge.
When particle & antiparticle collide they destroy each other producing energy.

Question 29

Hadrons

Answer 29

Heavy particles made of groups of quarks.
Baryons - 3 quarks
Mesons - 2 quarks
- Quark and antiquark

Question 30

Bosons

Answer 30

Graviton: Infinite range, weakest.
Photon: Electromagnetic, Infinite range, holds electrons in atoms.
Gluon: Holds protons together, strongest force, very short range.

Question 31

Work done in electric fields

Answer 31

Change in electrical potential energy.

Question 32

Linear accelerator

Answer 32

Accelerated in a vacuum pipe.
Adv. Simple acceleration
Disadv. Must be very long.

Question 33

Cyclotron

Answer 33

Start at centre.
Electrodes called dees accelerate particles by moving from one dee to another.
When it reaches edge its extracted.

Question 34

Synchrotron

Answer 34

Circular linear accelerator.
Magnets used to keep charged particles in the centre of the accelerator due to walls being very cold and could affect the acceleration rate if touched.
CERN.

Question 35

Threshold frequency

Answer 35

Each metal has a different fo.
When f>fo electrons are ejected with kinetic energy.