Equations

Question 1

Power? (PVI)

Answer 1

P
________ (PVI)
V X I

Power (W)
Voltage (V)
Current (Amps)

REMEMBER!!!!!!

If a transformer is only 90% efficient
The power (W) is lowered by 90%…. To do this, multiply the Pp by 0.9 to get the new Ps
This works with any efficiency! E.g
70% = multiply by 0.7

Question 2

Energy Tranfer?

Answer 2

Energy
——————-
Power X Time

                                     (EPT) Energy  (J) Power (W) Time (S)

Question 3

Calculate kWh?

Cost?

Answer 3

Kw X h

Cost = Units used X cost per unit

REMEMBER!!!!!
This is the only time KW and Hours are used to calculate!

Question 4

Efficiency?

Answer 4

T.I X EFF

Eff…..
U.O = useful output
E.g
70% is 0.7 when calculating!

Question 5

Waves?

Answer 5

Wavelength X Frequency

Wavespeed (m/s) (VFλ)
Wavelength (m)
Frequency (Hz)

Question 6

Another wave speed?

Answer 6

Speed X Time

Distance (m)
Speed (m/s)
Time (s)

Question 7

Density? (MVD)

Answer 7

M
_____ (MVD)
D X V

Mass(g or Kg)
Density(g/cm3 or kg/m3)
Volume (cm3 or m3)