1- Chapter 10 - Models

Question 1

What is radioactive decay?

Answer 1

A random process Breakdown of an unstable nuclei by releasing energy until its at a stable form modeled by exponential decay

Question 2

What is activity?

Answer 2

The number decaying per second

Question 3

Activity (a) =

Answer 3

pN/t = λN (in bequels Bq)

Question 4

Number left at time t (N)=

Answer 4

N₀e^{- λt}

Question 5

Rate of change of Number (dN/dt)=

Answer 5

• λN

Question 6

What is halflife?

Answer 6

Time it takes for half the neucli in a sample to decay

Question 7

halflife (t_1/2)=

Answer 7

ln2/λ

Question 8

Probability =

Answer 8

λt

Question 9

what is λ

Answer 9

The decay constant - Prob a neucleus will decay in one second.

Question 10

age of source =

Answer 10

t_1/2L (where L is number of half lifes)

Question 11

Number of halflives (L) =

Answer 11

Log₂(F) where F is the factor its been reduced by)

(from 2^L=F )

Question 12

Capaciance (C in Farads)=

Answer 12

Q/V Charge/pd

Question 13

Exponential decay equations for Q,I and V

Answer 13

Q=Q₀^-t/RC

V=V₀^-t/RC

I=I₀^-t/RC

Question 14

What is the time constant?

Answer 14

RC

Time it takes for it to discharge to 1/e of the former value

Question 15

Capistor Halflife=

Answer 15

RC ln2

Question 16

Energy Stored in a capacitor=

Answer 16

1/2 QV

1/2 Q²/C

1/2 CV²

Question 17

Displacement in SHM (x) =

Answer 17

Acosωt or Asinωt

Question 18

ω=

Answer 18

2πf or 2π/T

(k/m)^0.5

Angular velocity

Question 19

Period of oscilation (T) =

Answer 19

2π (m/k)^0.5

Question 20

a (in SHM) =

Answer 20

-ω²x or -kx/m

Question 21

Why do harmonic oscilators work?

Answer 21

There is a resoring force always pointed at the position of 0 displacement.

0 force at equilibrim position.

Question 22

Period of a pendulum

Answer 22

2π(L/g)^0.5

Question 23

What is resonance

Answer 23

The movement of an object caused by oscilations

Question 24

Natural frequency?

Answer 24

The frequency which will cuse the lagest oscilations when being vibrated at this speed.

Question 25

Whatsa dampning

Answer 25

the number of ocilations until the large amplitude has died away. Large dampening = Natural frequency is largesr but smaller amplitude opposite for smaller damnpning.

Question 26

How does dampening help?

Answer 26

* Removes energy from the system by converting kinetic energy to heat (via friction) * This reduces the amplitude of oscillations.

Question 27

Resonance curve

Answer 27

Curve tends to zero after peak