Equations

Question 1

velocity

Answer 1

v= d/t
d- distance (m)
t- time (s)

Question 2

Force

Answer 2

F=ma
m- mass (kg)
a- acceleration (m/s² )
derived units- kg -m/s²

Question 3

Area of a circle

Answer 3

A=πr²

Question 4

Volume of a sphere

Answer 4

v= 4/3πr³

Question 5

Equation of motion

Answer 5

v= u + at
v- final speed in metres/second (m/s).
u- initial speed in metres/ second (m/s)
a- acceleration in metres/ second (m/s²)

Question 6

equation of a straight line

Answer 6

y = mx + b
m represents the gradient of th Eline and b represents the y-axis intercept.

Question 7

Exponential relationships

Answer 7

y = kb ^x

Question 8

density

Answer 8

density = mass / volume

Question 9

thermal heat energy transfer

Answer 9

∆T = E / km
∆T- temp change (degrees celsius).
E- energy (J)
m- mass (kg)
k- specific heat (J/kg degrees celcius)/

Question 10

work

Answer 10

work = force x distance

Question 11

potential energy

Answer 11

PE = m x g x h
m- mass (kg)
g- gravitational field strength in newtons per kg, N/kg.
h- change in height in metres, m

Question 12

kinetic energy

Answer 12

KE = 1/2 mv²
m- mass in kilograms, kg
v- speed in metres per second, m/s

Question 13

Coulomb force (scalar form)

Answer 13

F= kq

Question 14

wave concept of EM

Answer 14

c= λv
c- speed of light (m/s)
λ- wavelength (m)
frequency (s-1)

Question 15

particle concept EM

Answer 15

E= hv
e- energy (KeV)
h- planks constant ( 4.13 x 10^-16 KeV sec).
v- frequency ( s-1)

Question 16

electric current

Answer 16

I = q/t
I- current in amperes (A)
Q- total change passing a boundary in coulombs (C).
f- time in seconds (s)

Question 17

resistance

Answer 17

R= p x L/A
r- resistance in ohms
l- length in metres
a- area in square metres
p- resistivity ohm metres

Question 18

ohms law

Answer 18

v= I x r
v- voltage in volts
I- current in amperes
r- resistance in ohms

Question 19

electric circuits- power

Answer 19

p= I x v
p- power in watts
I- current in amperes
v- voltage in volt

Question 20

electric circuits- energy

Answer 20

e= IVt
E- energy in joules (W)
I- Current in amperes
V- voltage in volts

Question 21

XR beam intensity

Answer 21

I2= I1 (D1/D2) ^2

Question 22

x ray tube heating- thermal energy

Answer 22

E= kV x mAs

Question 23

subject contrast

Answer 23

C= Ib- Ia / Ib

Question 24

attenuation- monochromatic beam

Answer 24

N = Noe -μ x
N- no. of transmitted photons
N0- no, of incident photons
μ - linear attenuation coefficient (cm-1)
x- absorber thickness (cm)

Question 25

thermal (heat) energy transfer

Answer 25

∆T= E/ km

∆T- temp change
E- energy
m- mass
k- specific heat