Physics OCR A A-Level (New Spec.) Flashcards Preview

A level Physics - OCR A (New spec.) > Physics OCR A A-Level (New Spec.) > Flashcards

Flashcards in Physics OCR A A-Level (New Spec.) Deck (22)
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1

Brownian Motion

Random motion small visible particles (in a fluid) as a result of thermal bombardment by much smaller, invisible molecules.

2

Ideal Gas Law

1. Large number particles
2. Rapidly, randomly
3. Collisions perfectly elastic
4. Negligible attractive forces
5. Time for collision negligible compared to time between
6. Particle = Negligible volume compared with volume of container

3

Ideal Gas

Gas where internal energy only randomly distributed KE

4

Boyle's Law

pV= Constant under conditions of constant temperature for a fixed mass

5

Charle's Law
&
Pressure-Temperature Law

V/T = Constant

P/T= Constant

6

Absolute Scale of Temperature

Scale measuring temperature independent of properties of any specific substance

7

What three findings led to the standard model through Rutherford's experiment?

Most a particles traveled through gold foil with little deflection (EMPTY SPACE)

a particles deflected away from nucleus, repulsive force necessary (NUCLEUS CHARGED)

8

Why is radioactive decay described as a random and spontaneous event?

RANDOM: (1) Cannot predict when a particular nucleus will decay (2) Each nucleus within sample has the same chance of decay per unit time.

SPONTANEOUS: (1) Not affected by presence of other nuclei in the sample (2) External factors i.e. pressure

9

Fundamental Particle

No internal structure & cannot be split into smaller particles

10

Ionising Radiation

Radiation removes electrons from atom leaving it positively charged

11

Radioactivity

Process by which unstable nuclei emit ionising radiation

12

Activity

Rate at which nuclei decay (Bequerels)

13

Annihalation

Complete destruction of particle and antiparticle that

14

Binding Energy

Minimum energy required to completely separate a nucleus into its constituent protons and neutrons

15

Thermal Neutrons

Neutron in fission reactor wuth mean KE similar to the Thermal energy of particles in the reactor core - slow neutrons

16

Induced fission

Nuclear fission occuring when a nucleus becomes unstable on absorbing aother particle (i.e. neutron)

17

Chain reaction

Reaction where neutrons from an earlier fission stage are responsible for further fission reactions leading to an exponential growth in the rate of reactions

18

Moderator

Substance used to slow down the fast neutrons produced in fission reactions so they can propagate the fission reaction

19

With what forces do Quarks & Leptons intra-act?

Quarks = Strong Nuclear force

Lepton= Weak Nuclear Force

20

Why are gamma photons emitted?

When nucleus dropping to its ground state following the emission of an a or b particle.

21

Measuring intensity of gamma radiation from source with a count rate may not be reliable, why?

- Gamma rays emitted in all directions so the detector only records those emitted in one direction.
- The efficiency of the detector is not 100%, the detector only records a fraction of the gamma rays that pass through it.
- The body of the sample itself may absorb some of the gamma rays inside of it.

22

Describe what happens when a proton and antiproton meet, in terms if the photons (slow-moving)

Two Y-photons released with equal energy and travelling in opposite directions