What do the Grade 10 Physics cards cover?

31 cards across 6 chapters of the national textbook: Vector Quantities, Uniformly Accelerated Motion, Elasticity and rigid body in static, Static and Current Electricity, Magnetism and 1 more. You can take any chapter one card at a time on the page itself.

Is there a national exam in Grade 10?

No. Ethiopia sets national exams in Grade 6, Grade 8 and Grade 12 only. These cards are for your school's own exams, and for the national exam that comes a few years later.

Where do these cards come from?

They are drafted from Grade 10 Physics, the Ministry of Education textbook for this grade. A second pass that cannot see the chapter then re-derives every formula, constant and table row, and anything it cannot confirm is held back instead of published.

Yes. Every card here is free to read and the printable sheet is free to download. Neither needs an account.

When was this last checked?

6 September 2026. Cards arrive chapter by chapter, and the line under each one says when that card was last read through.

Free short notes and revision cards

Grade 10 Physics

Grade 10 Physics on Temari has 31 revision cards, arranged by the chapters of the Ethiopian national curriculum. Every card says when the rule applies, what each symbol in it stands for, and the mistake students most often make with it. They are free to read and need no account.

31
Cards: 6
Chapters: 19
Formulas: 3
Reference tables: Grade 10 Physics
Textbook: Free
Price: 6 September 2026
Last checked

Everything31Formula19Rule6Common mistake3Reference table3

Vector Quantities

Adding Vectors AlgebraicallyCommon mistake

When you use it

When combining two or more vectors to determine their resultant magnitude.

Watch out

Never add vector magnitudes by simple scalar addition unless both vectors are parallel and point in the same direction.

Drafted from Grade 10 Physics, pages 6-27, then checked twice before it went up

Condition for Zero Resultant VectorRule

When you use it

When determining whether a given set of vectors can sum to a zero vector.

Watch out

Two vectors can produce a zero resultant only if they have equal magnitude and opposite directions. Three vectors of unequal magnitude can also sum to zero.

Drafted from Grade 10 Physics, pages 6-27, then checked twice before it went up

Direction of Resultant VectorFormula

\theta = \arctan\left(\frac{R_y}{R_x}\right)

\theta = \arctan\left(\frac{R_y}{R_x}\right)

$\theta$: Direction angle of the resultant vector $\text{degree}$
$R_y$: Vertical component of resultant vector $\text{unit of } R$
$R_x$: Horizontal component of resultant vector $\text{unit of } R$

When you use it

Use this to find the directional angle of a resultant vector from its horizontal and vertical components.

Watch out

State the reference direction explicitly such as north of east or south of west, not just the angle value.

Drafted from Grade 10 Physics, pages 6-27, then checked twice before it went up

Resultant of Perpendicular VectorsFormula

R = \sqrt{A^2 + B^2}

R = \sqrt{A^2 + B^2}

$R$: Magnitude of resultant vector $\text{unit of } A$
$A$: Magnitude of first perpendicular vector $\text{unit of } A$
$B$: Magnitude of second perpendicular vector $\text{unit of } B$

When you use it

Use this formula to calculate the magnitude of the resultant vector when two vectors act at a right angle to each other.

Watch out

This equation applies only when the angle between the two vectors is exactly 90 degrees.

Drafted from Grade 10 Physics, pages 6-27, then checked twice before it went up

Vector ResolutionFormula

A_x = A \cos\theta, \quad A_y = A \sin\theta

A_x = A \cos\theta, \quad A_y = A \sin\theta

$A_x$: Horizontal component of vector A $\text{unit of } A$
$A_y$: Vertical component of vector A $\text{unit of } A$
$A$: Magnitude of vector A $\text{unit of } A$
$\theta$: Angle of vector with horizontal axis $\text{degree}$

When you use it

Use this to resolve a single vector into its perpendicular horizontal and vertical components.

Watch out

Ensure the angle is measured from the horizontal axis. If measured from the vertical, cosine and sine swap roles.

Drafted from Grade 10 Physics, pages 6-27, then checked twice before it went up

Uniformly Accelerated Motion

Deceleration versus Negative AccelerationCommon mistake

When you use it

Reach for this distinction when a question asks about slowing down or motion in negative coordinates.

Watch out

Deceleration always reduces speed because acceleration is opposite to velocity. Negative acceleration only means pointing in the negative coordinate direction and can increase speed if velocity is also negative.

Drafted from Grade 10 Physics, pages 28-59, then checked twice before it went up

Displacement under Constant AccelerationFormula

s = v_0 t + \frac{1}{2} a t^2

s = v_0 t + \frac{1}{2} a t^2

$s$: displacement $m$
$v_0$: initial velocity $m\,s^{-1}$
$a$: acceleration $m\,s^{-2}$
$t$: time interval $s$

When you use it

Use when calculating displacement of an object moving with uniform acceleration over a known time interval.

Watch out

Acceleration must be constant throughout the motion. In free fall without air resistance, acceleration equals g.

Drafted from Grade 10 Physics, pages 28-59, then checked twice before it went up

Motion Graphs InterpretationReference tablePosition-time (s-t) · Velocity-time (v-t) · Acceleration-time (a-t)

Graph Type	Slope	Area Under Curve
Position-time ( $s-t$ )	Velocity	No physical meaning
Velocity-time ( $v-t$ )	Acceleration	Displacement
Acceleration-time ( $a-t$ )	No physical meaning	Change in velocity

When you use it

Use to identify physical quantities represented by slopes and enclosed areas on motion graphs.

Watch out

The area under a velocity-time graph yields displacement, which is not always equal to total distance.

Drafted from Grade 10 Physics, pages 28-59, then checked twice before it went up

Relative Velocity in One DimensionFormula

v_{AB} = v_A - v_B

v_{AB} = v_A - v_B

$v_{AB}$: relative velocity of A with respect to B $m\,s^{-1}$
$v_A$: velocity of object A $m\,s^{-1}$
$v_B$: velocity of object B $m\,s^{-1}$

When you use it

Use to determine the velocity of body A as observed from the reference frame of moving body B.

Watch out

Direction signs are critical: if objects move toward each other, assign one direction as positive and the opposite as negative.

Drafted from Grade 10 Physics, pages 28-59, then checked twice before it went up

Velocity under Constant AccelerationFormula

v = v_0 + a t

v = v_0 + a t

$v$: final velocity $m\,s^{-1}$
$v_0$: initial velocity $m\,s^{-1}$
$a$: acceleration $m\,s^{-2}$
$t$: time interval $s$

When you use it

Use to find the velocity of an object after it accelerates at a constant rate for time t.

Watch out

When an object slows down, acceleration has the opposite algebraic sign to velocity.

Drafted from Grade 10 Physics, pages 28-59, then checked twice before it went up

Elasticity and rigid body in static

Conditions of Static EquilibriumRule

When you use it

Use when solving for unknown forces or positions on a balanced, non moving rigid body.

Watch out

A system is only in complete static equilibrium when both net force is zero and net torque is zero at the same time.

Drafted from Grade 10 Physics, pages 60-81, then checked twice before it went up

Specific GravityFormula

\text{SG} = \frac{\rho}{\rho_{\text{water}}}

\text{SG} = \frac{\rho}{\rho_{\text{water}}}

$\text{SG}$: Specific gravity $\text{dimensionless}$
$\rho$: Density of substance $\text{kg}\,\text{m}^{-3}$
$\rho_{\text{water}}$: Density of water $\text{kg}\,\text{m}^{-3}$

When you use it

Use to determine how many times a substance is denser than water.

Watch out

Specific gravity is a pure ratio and has no units. Ensure both densities use identical units before dividing.

Drafted from Grade 10 Physics, pages 60-81, then checked twice before it went up

TorqueFormula

\tau = F_{\perp} r

\tau = F_{\perp} r

$\tau$: Torque $\text{N}\,\text{m}$
$\text{F}_{\perp}$: Perpendicular force $\text{N}$
$r$: Distance from pivot $\text{m}$

When you use it

Use to calculate the turning effect of a force applied at a distance from a pivot.

Watch out

Distance must be measured from the pivot point, and only the force component perpendicular to the lever arm produces torque.

Drafted from Grade 10 Physics, pages 60-81, then checked twice before it went up

Young's ModulusFormula

Y = \frac{F L_0}{A \Delta L}

Y = \frac{F L_0}{A \Delta L}

$Y$: Young's modulus $\text{N}\,\text{m}^{-2}$
$F$: Tensile force $\text{N}$
$L_0$: Original length $\text{m}$
$A$: Cross-sectional area $\text{m}^2$
$\Delta L$: Change in length $\text{m}$

When you use it

Use to calculate the stretch, tensile stress, tensile strain, or deformation of a solid material within its elastic limit.

Watch out

When wire diameter is given, use area = pi times diameter squared divided by 4, not just diameter squared.

Drafted from Grade 10 Physics, pages 60-81, then checked twice before it went up

Static and Current Electricity

Coulomb Law of ElectrostaticsFormula

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

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

$F$: electric force $\text{N}$
$k$: Coulomb constant $\text{N}\,\text{m}^2/\text{C}^2$
$q_1$: electric charge of first particle $\text{C}$
$q_2$: electric charge of second particle $\text{C}$
$r$: distance between charges $\text{m}$

When you use it

Use to calculate the electrostatic force of attraction or repulsion between two point charges.

Watch out

Remember to square the distance in the denominator. A negative result indicates attraction and a positive result indicates repulsion.

Drafted from Grade 10 Physics, pages 82-131, then checked twice before it went up

Electric Field StrengthFormula

E = k \frac{q}{r^2}

E = k \frac{q}{r^2}

$E$: electric field strength $\text{N}/\text{C}$
$k$: Coulomb constant $\text{N}\,\text{m}^2/\text{C}^2$
$q$: source electric charge $\text{C}$
$r$: distance from the charge $\text{m}$

When you use it

Use to calculate the electric field strength at a specific distance from a point charge.

Watch out

Distance r must be measured in metres and squared in the denominator.

Drafted from Grade 10 Physics, pages 82-131, then checked twice before it went up

Meter Connections in CircuitsCommon mistake

When you use it

Use when configuring meters to measure current or voltage in an electric circuit.

Watch out

Never connect an ammeter in parallel or a voltmeter in series. An ammeter in parallel draws excess current and gets damaged, while a voltmeter in series prevents current from flowing due to its high resistance.

Drafted from Grade 10 Physics, pages 82-131, then checked twice before it went up

Ohm LawFormula

\Delta V = I R

\Delta V = I R

$\Delta V$: potential difference $\text{V}$
$I$: electric current $\text{A}$
$R$: electrical resistance $\Omega$

When you use it

Use to relate potential difference, electric current, and resistance across an electrical component.

Watch out

Ohm law applies directly to Ohmic conductors where physical conditions such as temperature remain constant.

Drafted from Grade 10 Physics, pages 82-131, then checked twice before it went up

Resistor CombinationsReference tableSeries · Parallel

Connection	Equivalent resistance	Current	Potential difference
Series	$R_{eq} = R_1 + R_2 + \dots + R_n$	$I = I_1 = I_2 = \dots$	$\Delta V = \Delta V_1 + \Delta V_2 + \dots$
Parallel	$\frac{1}{R_{eq}} = \frac{1}{R_1} + \frac{1}{R_2} + \dots + \frac{1}{R_n}$	$I = I_1 + I_2 + \dots$	$\Delta V = \Delta V_1 = \Delta V_2 = \dots$

When you use it

Use when finding the equivalent resistance, branch currents, or voltages in series and parallel resistor circuits.

Watch out

For parallel combinations, solve for 1/R_eq first and take the reciprocal at the end to get R_eq.

Drafted from Grade 10 Physics, pages 82-131, then checked twice before it went up

Earthing and the third pin on a plugRuleLive wire · Neutral wire · Earth wire · +3

Part of the circuit	In normal use	When a fault happens
Live wire	Brings current to the appliance at about 220 V with respect to the earth.	If it touches the metal body, the body goes live until the supply is cut off.
Neutral wire	Returns the same current to the supply and sits near 0 V.	It carries the working current, so it can never stand in for the earth wire.
Earth wire	Carries no current at all and holds the metal body at earth potential.	Gives the fault current a low-resistance path to the ground, so a large current flows.
Fuse or MCB	Sits in the live wire and never in the neutral.	The large fault current blows the fuse or trips the MCB, and the appliance is disconnected.
Two-pin plug	Gives a metal-bodied appliance no earth path.	A fault can leave the casing live. A double-insulated appliance with a plastic casing is built for two pins on purpose.
The socket in an Ethiopian wall	European round-pin, 220 V at 50 Hz, with the earth contact often made by clips on the sides.	The three rectangular pins drawn on most revision sheets are the British pattern, where the earth pin is longer and thicker so it makes contact first and breaks last.

When you use it

Use when a question asks why a metal-bodied appliance such as a refrigerator, an electric mitad or a water heater needs a third wire. The earth wire protects the person touching it: it gives fault current a low-resistance path, so the fuse blows or the MCB trips before anyone is hurt.

Watch out

Students treat the earth wire and the neutral wire as the same thing because both measure near 0 V, and some join the earth pin straight to the neutral to save a wire. They are not the same. In normal use the neutral carries the full working current while the earth carries none, so if a neutral used as an earth breaks anywhere upstream, the metal body is joined through the motor to the live wire and sits at 220 V. The other half of the same mistake is fitting the fuse in the neutral: it still blows, but the appliance stays connected to the live wire and is dangerous to touch. The rule is short: the fuse goes in the live wire, the earth goes to the metal body, and the neutral carries the current back to the supply.

Magnetism

Forces between parallel currentsRule

When you use it

Use this rule to predict whether two parallel current-carrying wires will attract or repel each other.

Watch out

Parallel currents in the same direction attract and opposite directions repel. This is the opposite behaviour of electrostatic charges.

Drafted from Grade 10 Physics, pages 132-155, then checked twice before it went up

Magnetic field of a straight wireFormula

B = \frac{\mu_0 I}{2\pi r}

B = \frac{\mu_0 I}{2\pi r}

$B$: magnetic field strength $\text{T}$
$\mu_0$: permeability of free space $\text{T}\,\text{m}\,\text{A}^{-1}$
$I$: current $\text{A}$
$r$: radial distance from wire $\text{m}$

When you use it

Use this formula to calculate the magnetic field strength at a distance r from a long straight wire carrying electric current.

Watch out

Convert distance r from centimetres to metres before calculating.

Drafted from Grade 10 Physics, pages 132-155, then checked twice before it went up

Magnetic force on a current-carrying wireFormula

F = I l B \sin\theta

F = I l B \sin\theta

$F$: magnetic force $\text{N}$
$I$: current $\text{A}$
$l$: length of wire in field $\text{m}$
$B$: magnetic field strength $\text{T}$
$\theta$: angle between current and magnetic field $\text{rad}$

When you use it

Use this formula to calculate the deflecting magnetic force on a straight conductor carrying current in an external magnetic field.

Watch out

The angle theta is measured between the direction of current flow and the magnetic field lines.

Drafted from Grade 10 Physics, pages 132-155, then checked twice before it went up

Magnetic force on a moving chargeFormula

F = q v B \sin\theta

F = q v B \sin\theta

$F$: magnetic force $\text{N}$
$q$: charge $\text{C}$
$v$: speed of charge $\text{m}\,\text{s}^{-1}$
$B$: magnetic field strength $\text{T}$
$\theta$: angle between velocity and magnetic field $\text{rad}$

When you use it

Use this formula to find the magnetic force exerted on a charged particle moving through an external magnetic field.

Watch out

The force is zero when the charge moves parallel to the magnetic field direction because sin 0 is zero.

Drafted from Grade 10 Physics, pages 132-155, then checked twice before it went up

Right hand thumb rule for a straight wireRuleWhich way does the field circle the wire? · What shape are the field lines? · Which current does the thumb follow? · +3

Question	What to do	What it tells you
Which way does the field circle the wire?	Grip the wire with your right hand, thumb lying along the conventional current.	Your curled fingers point the way the field circles the wire.
What shape are the field lines?	Look at a plane cut at right angles to the wire.	Closed circles centred on the wire, all lying in that plane.
Which current does the thumb follow?	Conventional current: from the positive terminal to the negative terminal outside the source.	That is the opposite of the electron flow.
Which way does the field point at one chosen place?	Draw the circle through that point and take the tangent to it.	The field is at right angles to the wire and to the line from the wire to that point.
How strong is the field?	Use $B = \dfrac{\mu_0 I}{2\pi r}$ , where $r$ is the perpendicular distance from the wire's axis and $\mu_0 = 4\pi \times 10^{-7}\,\text{T}\cdot\text{m/A}$ .	Double the current and the field doubles. Double the distance and the field halves.
When does that formula stop working?	Check the shape of the conductor before you use it.	It belongs to a long straight wire only. A circular loop and a solenoid each have their own formula.

When you use it

Use to find which way the magnetic field circles a straight wire that is carrying current. Grip the wire with your right hand and lay your thumb along the conventional current: your curled fingers then point the way the field goes round.

Watch out

The commonest slip is running the rule backwards, curling the fingers along the wire and sweeping the thumb around it. That reverses every answer. The thumb lies along the wire pointing the way the conventional current flows, and the fingers do the circling. The second trap is the distance. The field falls as 1/r, so a point twice as far from the wire feels half the field and not a quarter, and a student who carries the inverse square habit over from Coulomb's law gets it wrong every time.

Magnetic domains and why poles attract or repelRuleA plain piece of iron · The same iron being magnetized · A saturated magnet · +4

Situation	What the domains are doing	What you observe
A plain piece of iron	The domains point in random directions, so their effects cancel.	The material shows no magnetism outside itself.
The same iron being magnetized	Domains already pointing the right way grow, and the rest swing round to join them.	Their effects add up and the material becomes a strong magnet.
A saturated magnet	Every domain is already lined up.	The magnet cannot be made any stronger.
A magnet heated strongly, hammered or dropped	The domains are knocked back out of line.	The magnet loses its strength.
An iron nail held near one pole	The magnet nearby lines up the nail's own domains first.	The nail is attracted by either pole, so attraction proves nothing.
Two magnets brought together	Each magnet sits in the field the other one's aligned domains produce.	Like poles repel and unlike poles attract.
A magnet broken in two	Each piece still holds its own aligned domains.	Every piece has both a north pole and a south pole.

When you use it

Use when a question asks how a piece of iron becomes a magnet, why a magnet loses its strength, or whether two objects will attract or repel. Domains say where a permanent magnet's field comes from, and the push or pull is each magnet sitting in the field of the other.

Watch out

Attraction on its own does not prove that something is a magnet. A magnet attracts an unmagnetized iron bar from either pole, because it lines up the bar's own domains first. Repulsion is the only certain test that both objects are magnets. The same trap catches the compass: the magnetic pole sitting near the geographic North is a magnetic south pole, and that is exactly why the needle's north end swings towards it.

Unit 6

Color Addition of LightReference tableRed · Blue

Primary Color 1	Primary Color 2	Resulting Secondary Color
Red	Green	Yellow
Red	Blue	Magenta
Blue	Green	Cyan

When you use it

Use to determine the secondary color produced by mixing primary colors of light.

Watch out

Color addition applies to light beams, not to mixing physical paint pigments.

Drafted from Grade 10 Physics, page 156 onwards, then checked twice before it went up

Lens EquationFormula

\frac{1}{v} - \frac{1}{u} = \frac{1}{f}

\frac{1}{v} - \frac{1}{u} = \frac{1}{f}

$v$: Image distance $\text{m}$
$u$: Object distance $\text{m}$
$f$: Focal length $\text{m}$

When you use it

Use to find object distance, image distance, or focal length for thin spherical lenses.

Watch out

The lens formula has a minus sign before the 1/u term, unlike the mirror formula.

Drafted from Grade 10 Physics, page 156 onwards, then checked twice before it went up

Mirror EquationFormula

\frac{1}{v} + \frac{1}{u} = \frac{1}{f}

\frac{1}{v} + \frac{1}{u} = \frac{1}{f}

$v$: Image distance $\text{m}$
$u$: Object distance $\text{m}$
$f$: Focal length $\text{m}$

When you use it

Use to calculate image position, object position, or focal length for spherical mirrors.

Watch out

Focal length is positive for concave mirrors and negative for convex mirrors.

Drafted from Grade 10 Physics, page 156 onwards, then checked twice before it went up

Power of a LensFormula

P = \frac{1}{f}

P = \frac{1}{f}

$P$: Power of lens $\text{D}$
$f$: Focal length $\text{m}$

When you use it

Use to calculate lens power from focal length or determine corrective lenses for vision defects.

Watch out

Focal length must be converted to metres before calculating power in diopters.

Drafted from Grade 10 Physics, page 156 onwards, then checked twice before it went up

Snell Law of RefractionFormula

n_1 \sin\theta_1 = n_2 \sin\theta_2

n_1 \sin\theta_1 = n_2 \sin\theta_2

$n_1$: Refractive index of first medium $1$
$\theta_1$: Angle of incidence $^\circ$
$n_2$: Refractive index of second medium $1$
$\theta_2$: Angle of refraction $^\circ$

When you use it

Use when finding angles or refractive indices as light passes between two optical media.

Watch out

Angles must be measured relative to the normal line, not relative to the boundary surface.

Drafted from Grade 10 Physics, page 156 onwards, then checked twice before it went up

The same subject in other years

An exam paper keeps asking for what the year below taught. Those cards are here too.

Your other Grade 10 subjects

Everything else in this year that has cards so far.

Questions students ask

What do the Grade 10 Physics cards cover?: 31 cards across 6 chapters of the national textbook: Vector Quantities, Uniformly Accelerated Motion, Elasticity and rigid body in static, Static and Current Electricity, Magnetism and 1 more. You can take any chapter one card at a time on the page itself.
Is there a national exam in Grade 10?: No. Ethiopia sets national exams in Grade 6, Grade 8 and Grade 12 only. These cards are for your school's own exams, and for the national exam that comes a few years later.
Where do these cards come from?: They are drafted from Grade 10 Physics, the Ministry of Education textbook for this grade. A second pass that cannot see the chapter then re-derives every formula, constant and table row, and anything it cannot confirm is held back instead of published.
Is this free?: Yes. Every card here is free to read and the printable sheet is free to download. Neither needs an account.
When was this last checked?: 6 September 2026. Cards arrive chapter by chapter, and the line under each one says when that card was last read through.

Revise, then test yourself

Temari turns these cards into practice questions and marks them as you go, with an AI tutor to explain anything that did not land.

Start free