IEB Grade 12 Physics Formula Review

Flashcards covering gravitational fields, electric fields, circuits, electrodynamics, and photon physics based on the Grade 12 National Senior Certificate handbook.

What is the formula for the gravitational force between two masses?

$$F = \frac{G m_1 m_2}{r^2}$$

How is gravitational field strength ($g$) calculated relative to force and mass?

$$g = \frac{F}{m}$$

What is the formula for gravitational field strength ($g$) at a distance $r$ from a point mass $M$?

$$g = \frac{G M}{r^2}$$

What is the formula for Coulomb's Law of electric force?

$$F = \frac{k q_1 q_2}{r^2}$$

How is electric field strength ($E$) defined in terms of force and charge?

$$E = \frac{F}{q}$$

What is the expression for electric field strength ($E$) at a distance $r$ from a point charge $Q$?

$$E = \frac{k Q}{r^2}$$

What is the equation relating current ($I$), charge ($q$), and time ($t$)?

$$I = \frac{q}{t}$$

How is potential difference ($V$) defined in terms of work ($W$) and charge ($q$)?

$$V = \frac{W}{q}$$

What is the expression for resistance ($R$) according to Ohm's Law?

$$R = \frac{V}{I}$$

What is the formula for $emf$ incorporating external and internal resistance?

$emf = I(R_{ext} + r)$ OR $emf = V_{load} + V_{internal resistance}$

How do you calculate total resistance ($R_S$) for resistors in series?

$$R_S = R_1 + R_2 + \text{......}$$

How is the total resistance ($R_P$) calculated for resistors in parallel?

$$\frac{1}{R_P} = \frac{1}{R_1} + \frac{1}{R_2} + \text{.....}$$

What is the definition of power ($P$) in terms of work ($W$) and time ($t$)?

$$P = \frac{W}{t}$$

What are the three main formulas for calculating work ($W$) in an electric circuit?

$W = VIt$ OR $W = I^2Rt$ OR $W = \frac{V^2}{R} t$

What are the three main formulas for calculating electrical power ($P$)?

$P = VI$ OR $P = I^2R$ OR $P = \frac{V^2}{R}$

What is the formula for magnetic flux ($\Phi$)?

$$\Phi = BA\text{cos}(\theta)$$

What is Faraday's Law of induction formula for $emf$?

$$emf = -N \frac{\DeltaΦ}{\Delta t}$$

What is the formula for the force ($F$) on a current-carrying conductor in a magnetic field?

$$F = IBℓ \text{sin}(\theta)$$

What equation relates the potential difference and current between the primary and secondary coils of a transformer?

$$V_p I_p = V_s I_s$$

What is the turns ratio equation for a transformer?

$$\frac{N_s}{N_p} = \frac{V_s}{V_p}$$

What is the wave equation for the speed of light ($c$)?

$$c = f λ$$

What are the formulas for the energy ($E$) of a photon?

$E = hf$ OR $E = \frac{hc}{λ}$

What is the photoelectric effect equation?

$$E = W_0 + E_{K(max)}$$

How is the work function ($W_0$) calculated?

$$W_0 = hf_0$$

What is the formula for the maximum kinetic energy ($E_{K(max)}$) of an electron?

$$E_{K(max)} = \frac{1}{2} m v_{max}^2$$