Physics holds 894 questions with answers, free to read and with no account needed. They are grouped into 1 category: Physics.
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Answer: A. Variable acceleration
A velocity-time graph represents how an object speed changes continuously over a given time interval. When this graph forms a parabolic curve, velocity changes non-linearly as time progresses forward. Non-linear velocity...
Answer: B. f -32/9 =c/5
The standard conversion formula relating Fahrenheit and Celsius temperatures is established. Subtracting 32 from Fahrenheit and dividing by 9 equals Celsius divided by 5. This mathematical ratio accurately bridges the tw...
Answer: C. Static equilibrium
Static equilibrium describes objects at rest where net force and net torque equal zero. Dynamic equilibrium involves objects moving at constant linear or angular velocity through space. Since static equilibrium lacks mot...
Answer: B. child does more work than man
Work done equals the product of applied force and the vertical displacement distance lifted. The adult lifts a forty kilogram weight by one meter, performing four hundred joules of work. The child lifts a ten kilogram we...
Answer: B. Absorbed
Thermal equilibrium populations feature more atoms in lower ground states than excited states. Incoming high-energy photons interact with these ground state atoms by transferring their energy. Atoms absorb the photon ene...
Answer: B. Valence band
The valence band is the energy band containing the valence electrons responsible for chemical bonding. Electrons residing in this band are normally bound to specific atoms within the crystal lattice. Thermal energy can e...
Answer: D. centripetal force
Centripetal force is always directed perpendicular to the instantaneous velocity vector of a moving particle. Work is calculated as force multiplied by displacement times the cosine of the angle between them. Since the a...
Answer: C. The resistance of copper decreases and that of germanium increases.
Cooling a metal (copper) decreases its resistance, while cooling a semiconductor (germanium) increases its resistance. Metals have positive temperature coefficients, meaning resistance drops as thermal vibrations decreas...
Answer: C. Inverted population
Population inversion occurs when upper energy levels hold more atoms than lower levels. Excited state atom accumulation exceeds ground state populations during laser operation. Inverted populations violate thermal equili...
Answer: B. 0.5 hertz
A standard seconds pendulum is defined as having a complete time period of precisely two seconds. Frequency is calculated mathematically as the inverse of the time period of oscillation. Dividing one by two seconds yield...
Answer: B. Paschen series is a line spectrum in the infra red.
The Paschen series consists of discrete spectral emission lines in infrared. Electrons transitioning to the third energy level emit specific photon wavelengths. These discrete frequency lines form a characteristic atomic...
Answer: B. in front of the retina
Concave lenses diverge incoming light rays before they enter the human eye structure. Myopic eyes possess excessive optical power that focuses distant light rays too early. Unassisted nearsighted eyes naturally focus ima...
Answer: A. Percentage uncertainties are added
Multiplying or dividing measured values requires combining their fractional or percentage errors. Calculus derivations using logarithms prove that relative uncertainties accumulate directly. Adding percentage uncertainti...
Answer: D. straight line
Ohm law states that electrical current is directly proportional to voltage under constant resistance conditions. Plotting voltage on one axis and current on another produces a linear mathematical relationship. The result...
Answer: C. Lead
Lead provides exceptional shielding against gamma radiation due to its high density. High atomic numbers in lead atoms increase the probability of photon absorption interactions. Dense materials block penetrating electro...
