High School Physics practice questions and exam guide

Ohm's law:

1. V = IR (voltage = current × resistance)
2. V = IR
3. V = I + R
4. V = I/R
5. V = I²R

Answer: A — V = IR (voltage = current × resistance)

Ohm's law: V = IR. Voltage (V) = current (I) × resistance (R). Linear relationship for ohmic materials. Power dissipated: P = IV = I²R = V²/R. Foundation of circuits.

Wave equation: v = ?

1. v = f + λ
2. v = f/λ
3. v = f·λ (wave speed equals frequency times wavelength)
4. v = λ/f
5. v = f²λ

Answer: C — v = f·λ (wave speed equals frequency times wavelength)

Wave speed v = f·λ. Period T = 1/f. Wave speed depends on medium properties. Light in vacuum: v = c ≈ 3 × 10⁸ m/s. Sound in air: v ≈ 343 m/s (at 20°B).

Conservation of energy applies if:

1. Friction always
2. No external work and no non-conservative forces remove energy; mechanical energy conserved in isolated system
3. Always universally (within bookkeeping of all forms)
4. Only thermal
5. Only motion

Answer: C — Always universally (within bookkeeping of all forms)

Energy is universally conserved (modern physics broadens this). For mechanical energy specifically: conserved when only conservative forces (gravity, springs) act. Friction etc. convert ME to heat. Total energy (incl. thermal, internal) always conserved.

Projectile launched at angle θ with speed v. Range:

1. R = vt
2. R = v²cos(θ)/g
3. R = v/g
4. R = v²sin(2θ)/g

Answer: D — R = v²sin(2θ)/g

D) Standard. A/B/C) Each is incorrect.

Power is:

1. Same as energy
2. Same as force
3. Same as work
4. Rate of doing work or transferring energy — P = W/t (watts = joules/second); or P = F·v at constant velocity

Answer: D — Rate of doing work or transferring energy — P = W/t (watts = joules/second); or P = F·v at constant velocity

D) Standard definition. A/B/C) Each is incorrect.

What is the unit of energy in SI?

1. Newton
2. Pascal
3. Watt
4. Joule (J = N·m = kg·m²/s²)
5. Hertz

Answer: D — Joule (J = N·m = kg·m²/s²)

Energy in SI: joules (J). J = N·m (force × distance) = kg·m²/s². Watt = J/s (power). Other energy units: kWh, calorie, eV (1 eV ≈ 1.6×10⁻¹⁹ J). Important to know SI units.

The magnetic force on a charged particle is:

1. F = q · B alone
2. F = q · (v × B) — perpendicular to both v and B
3. F = q · v alone
4. F = q + v

Answer: B — F = q · (v × B) — perpendicular to both v and B

B) Lorentz magnetic force. A/C/D) Each is incorrect.

An object in circular motion experiences CENTRIPETAL FORCE directed:

1. Outward (centrifugal — but that's apparent, not real)
2. Toward the center of the circle (causes circular motion; F_c = mv²/r)
3. Tangent to circle
4. Random direction
5. Vertical only

Answer: B — Toward the center of the circle (causes circular motion; F_c = mv²/r)

Centripetal force: real net force pointing TOWARD center. F_c = mv²/r. Source varies: tension (string), gravity (orbits), friction (car turning). Centrifugal 'force' is apparent (rotating reference frame), not real. Common point of confusion.

Orbital motion (e.g., satellite):

1. Cannot be predicted
2. Has no force
3. Constant speed regardless of distance
4. Gravity provides the centripetal force needed for circular orbit — orbital speed depends on radius and mass of body orbited (v = √(GM/r) for circular orbits)

Answer: D — Gravity provides the centripetal force needed for circular orbit — orbital speed depends on radius and mass of body orbited (v = √(GM/r) for circular orbits)

D) Standard. A/B/C) Each is incorrect.

AP Physics 1 exam format:

1. 50 MC (90 min) + 5 FRQ (90 min); algebra-based; covers mechanics, waves, sound, intro electricity
2. Calculus required
3. Random
4. Only mechanics

Answer: A — 50 MC (90 min) + 5 FRQ (90 min); algebra-based; covers mechanics, waves, sound, intro electricity

A) Standard. B) That's AP Physics C. C/D) Each is incorrect.

Wave speed equation:

1. v = f/λ
2. v = f
3. v = λ
4. v = fλ

Answer: D — v = fλ

D) Standard. A/B/C) Each is incorrect.

Buoyancy (Archimedes' principle):

1. Upward force on an object in fluid equals weight of fluid displaced — explains why objects float (if buoyancy ≥ weight) or sink; affects ships, hot air balloons, submarines
2. Has no real effect
3. Down force
4. Equals object's volume

Answer: A — Upward force on an object in fluid equals weight of fluid displaced — explains why objects float (if buoyancy ≥ weight) or sink; affects ships, hot air balloons, submarines

A) Standard. B/C/D) Each is incorrect.

State the work-energy theorem.

The net work done on an object equals its change in kinetic energy: W_net = ΔKE.

What is diffraction?

The bending of waves around obstacles or through openings; most noticeable when the opening size is comparable to the wavelength.

What is electric charge measured in?

Coulombs (C).

What is inertia?

An object's resistance to changes in its state of motion. Mass is a measure of inertia.

Two complementary launch angles (e.g., 30° and 60°) give the same range. Why?

Because sin(2θ) = sin(180°-2θ); sin 60° = sin 120°.

What is the difference between distance and displacement?

Distance is the total path length traveled (scalar). Displacement is the straight-line vector from start to end position.