Intermediate physics questions

43 flashcards by Matt

Multiple choice

Which quantity is conserved in an isolated collision? A) Force B) Momentum C) Power D) Temperature?

B) Momentum. Total momentum remains constant when no external net force acts on the system: p_total before = p_total after.

How does doubling an object’s speed affect its kinetic energy? A) Doubles B) Quadruples C) Halves D) Unchanged?

B) Quadruples. Kinetic energy is KE = 1/2 mv^2, so the squared speed makes doubling v increase KE by a factor of four.

Which change increases the period of a simple pendulum? A) Greater mass B) Longer length C) Larger bob D) Stronger material?

B) Longer length. For small oscillations, T = 2π√(L/g), so increasing length increases the period; the bob’s mass does not affect it.

A 5 kg object accelerates at 2 m/s^2. What net force acts? A) 2.5 N B) 7 N C) 10 N D) 25 N?

C) 10 N. Newton’s second law gives F = ma = (5 kg)(2 m/s^2) = 10 N.

Why does a passenger lurch forward when a stopped bus suddenly moves? A) Gravity B) Inertia C) Friction D) Weight?

B) Inertia. Newton’s first law states that the passenger’s body tends to remain at rest until an external force accelerates it.

A 2 kg object moving at 6 m/s has what momentum? A) 3 kg·m/s B) 8 kg·m/s C) 12 kg·m/s D) 36 kg·m/s?

C) 12 kg·m/s. Momentum is p = mv, so p = (2 kg)(6 m/s) = 12 kg·m/s in the direction of motion.

Which change doubles the work done by a constant force? A) Halve force B) Halve distance C) Double force D) Reverse time?

C) Double force. For parallel force and displacement, work is W = Fd; doubling F while keeping d unchanged doubles W.

A 4 kg object is lifted 3 m. Using g = 10 m/s^2, what gravitational potential energy is gained? A) 12 J B) 40 J C) 120 J D) 240 J?

C) 120 J. Gravitational potential energy is U = mgh = (4 kg)(10 m/s^2)(3 m) = 120 J.

Which statement correctly describes electric charge? A) It is measured in ohms B) It is conserved C) It has no sign D) It flows only in insulators?

B) It is conserved. Electric charge can move between objects, but the total charge of an isolated system remains constant. Charge is measured in coulombs (C) and may be positive or negative.

Which direction does the electric field point near a positive point charge? A) Toward it B) Away from it C) Circularly around it D) Randomly?

B) Away from it. The electric field direction is defined as the force direction on a positive test charge. For a negative source charge, the field points toward the charge.

What does a potential difference of 12 volts mean? A) 12 coulombs per second B) 12 joules per coulomb C) 12 ohms per ampere D) 12 newtons per meter?

B) 12 joules per coulomb. Potential difference is energy transferred per unit charge: V = W/Q. A 12 V source supplies 12 J of energy for each coulomb moved.

Which equation relates potential difference, current, and resistance? A) V = IR B) V = I/R C) R = VI D) I = VR?

A) V = IR. Ohm’s law states that potential difference V equals current I multiplied by resistance R. Resistance is measured in ohms (Ω), current in amperes (A), and voltage in volts (V).

What happens to current if resistance doubles while voltage stays constant? A) It doubles B) It halves C) It quadruples D) It remains unchanged?

B) It halves. From I = V/R, current is inversely proportional to resistance when voltage is fixed. Doubling R changes the current from I to I/2.

Which quantity is the distance between matching points on consecutive waves? A) Amplitude B) Wavelength C) Frequency D) Period?

B) Wavelength. It is the spatial distance between corresponding points, such as crest to crest. Wave speed follows v = fλ, where f is frequency and λ is wavelength.

A wave has a frequency of 5 Hz. What is its period? A) 0.02 s B) 0.2 s C) 5 s D) 25 s?

B) 0.2 s. Frequency and period are reciprocals: T = 1/f = 1/5 s. The wave completes five cycles each second.

What happens when two waves meet in phase? A) Destructive interference B) Constructive interference C) Refraction D) Polarization?

B) Constructive interference. In-phase waves reinforce one another, producing a resultant amplitude equal to the sum of their individual amplitudes.

Which condition produces resonance in an oscillating system? A) Maximum damping B) Driving frequency matching natural frequency C) Zero amplitude D) Random forcing?

B) Driving frequency matching natural frequency. Energy transfer is then most efficient, causing the oscillation amplitude to become unusually large, especially when damping is small.

In simple harmonic motion, which statement about acceleration is correct? A) It is constant B) It points away from equilibrium C) It is proportional and opposite to displacement D) It is always zero?

C) It is proportional and opposite to displacement. The relationship is a = -ω^2x, so acceleration increases with displacement and always points toward the equilibrium position.

Which statement correctly defines temperature? A) Total heat B) Average kinetic energy C) Thermal mass D) Energy transfer?

B) Average kinetic energy. Temperature measures the average kinetic energy of particles, while thermal energy depends on both particle energy and the amount of matter.

Which heat-transfer method can occur through empty space? A) Conduction B) Convection C) Radiation D) Diffusion?

C) Radiation. Electromagnetic waves transfer thermal energy through a vacuum, allowing sunlight to heat Earth across space.

What happens to a system’s internal energy when it absorbs heat and does no work? A) Decreases B) Increases C) Stays constant D) Becomes zero?

B) Increases. The first law gives ΔU = Q - W; with W = 0 and positive Q, the system’s internal energy increases by the absorbed heat.

At constant temperature, what happens to a gas’s volume if its pressure doubles? A) Doubles B) Halves C) Quadruples D) Does not change?

B) Halves. Boyle’s law states that pressure and volume are inversely proportional at constant temperature: P1V1 = P2V2.

Which process transfers heat from a warmer object to a cooler one? A) Spontaneously B) Only with work C) From cold to hot D) Without energy transfer?

A) Spontaneously. The second law of thermodynamics states that heat naturally flows from higher temperature to lower temperature unless external work intervenes.

Which description correctly defines a magnetic field? A) Region exerting magnetic forces B) Stored electric charge C) Flow of heat D) Sound wave?

A) Region exerting magnetic forces. A magnetic field surrounds magnets and moving charges and is represented by field lines directed from a north pole to a south pole outside the magnet.

A charged particle moves parallel to a magnetic field. What magnetic force acts on it? A) Maximum B) Zero C) qvB D) Infinite?

B) Zero. The magnetic force is F = qvB sin(theta). For parallel motion, theta = 0 degrees and sin(0) = 0, so the magnetic field does not deflect the particle.

What determines the direction of force on a current-carrying wire? A) Right-hand rule B) Lenz's law C) Archimedes' principle D) Snell's law?

A) Right-hand rule. Point your fingers in the magnetic-field direction and your thumb in the conventional-current direction; the force direction follows the perpendicular orientation given by the rule.

Which change produces the greatest induced voltage in a coil? A) Slower flux change B) Faster flux change C) Fewer turns D) Constant flux?

B) Faster flux change. Faraday's law states that induced voltage increases with the rate of change of magnetic flux and with the number of coil turns: induced voltage = -N times change in flux divided by time.

Why does an induced current oppose the change that produces it? A) Conservation of energy B) Gravity C) Inertia only D) Charge creation?

A) Conservation of energy. Lenz's law gives the induced current a direction that opposes the changing magnetic flux, preventing energy from appearing without work being done.

Which law gives the angle of reflection? A) θr = θi B) θr = 2θi C) θr = θi/2 D) θr = 90°?

A) θr = θi. The angle of reflection equals the angle of incidence, with both angles measured from the normal to the reflecting surface.

What causes light to bend when entering glass from air? A) Diffraction B) Refraction C) Polarization D) Reflection?

B) Refraction. Light changes speed when it crosses into a different medium, causing its direction to change unless it enters perpendicular to the surface.