Units and formulas

Question 1

Frequency is measured in what unit? What is the formula for frequency?

Answer 1

hertz(Hz)

s^-1

Question 2

Force is measured in what unit? What is the formula for force?

Answer 2

Newton, N

kg * m/s²

Question 3

Energy/work is measured in what unit? What is the formula for energy/work?

Answer 3

Joules (j)

N*m

Question 4

Power is measured in what unit? What is the formula for power?

Answer 4

Watts (W)

J/s

also

P = Vi (voltage*current)

Question 5

Electric charge is measured in what unit? What is the formula for electric charge?

Answer 5

Coulomb (C)

A*s

Question 6

Electric potential is measured in what unit? What is the formula for electric potential?

Answer 6

Volts (V)

J/C

Question 7

Electric resistance is measured in what unit? What is the formula for electric resistance?

Answer 7

ohm(Ω)

V/A

Question 8

Electric conductance is measured in what unit? What is the formula for electric conductance?

Answer 8

siemens(S) - mathematical symbol is G

A/V

Question 9

What do the following letters symbolise?

V =

W =

q & Q =

i =

t =

P =

Answer 9

V = voltage in volts

W = the energy (work) in joules

q & Q = the charge in Coulombs (intantaneous - q) (static charge - Q)

i = current measured in Amps

t = time in s

P = power measured in Watts

Question 10

What is the difference beteween positive and negative power?

Answer 10

Energy that is dissipated (lost) is considered positive.

e.g. a 60W lightbulb dissipates that energy, but is considered a positive wattage.

Question 11

What is the equation for voltage (V)?

Answer 11

V = iR

Question 12

What is the equation for current (i)?

Answer 12

i = V/R

Question 13

What is the equation for Power (W)?

Answer 13

W = iV

Question 14

What is the equation for Resistance (Ω - ohms)?

Answer 14

Ω = V/A

or

Ω = pl / A

where *p = *resistivity of the material

*l *= length of the material

A = area (cross sectional area)

Question 15

If V = iR and P = iV, how else could P be calculated in relation to R?

Answer 15

V = iR

P = iV

so

P =i*(iR) = i²R = V²/R

Question 16

What is the scientific notation for:
Tera
Giga
Mega
Kilo

Answer 16

10¹²

10⁹

10⁶

10³

Question 17

1 electron is equal to how many Coulombs?

1 Coulomb is equal to how many electrons?

Answer 17

1e = 1.602*10^{-19 C}

1C = 6.242*10¹⁸e