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: C. 1/10th
Ice is about nine tenths as dense as sea water, so a floating iceberg displaces its own weight by sinking roughly nine tenths of its volume. Only about a tenth shows above the waterline. The hidden nine tenths is also wh...
Answer: C. Raleigh
Lord Rayleigh formulated the optical resolution criterion for circular aperture instruments. The equation theta equals 1.22 lambda over D determines minimum resolvable angle. It accounts for light diffraction effects pas...
Answer: C. Three
Three vectors of unequal magnitude can sum to zero if they form a closed triangle. Coplanaer vectors arranged head-to-tail without remaining gaps produce a zero resultant vector. Fewer than three unequal vectors cannot p...
Answer: D. exerts a force if the charged particle is moving perpendicular to the magnetic field lines
A magnetic field exerts a maximum force on a charged particle when it moves perpendicularly to the field lines. The magnetic force is proportional to the cross product of velocity and magnetic field vectors. Particles mo...
Answer: B. increases
Pushing two like-charged electrons together requires performing external mechanical work against electrostatic repulsion forces. This applied work is stored directly inside the two-particle system as increased electrosta...
Answer: D. use a very strong magnetic field
Using a very strong magnetic field maximizes the deflecting torque per unit current in a galvanometer. Stronger magnetic flux density increases the magnetic force acting on the current-carrying coil. Higher deflecting to...
Answer: D. 12N, 5N, 15N
Concurrent forces can achieve static equilibrium only if their vector sum equals zero and their lines of action intersect. The triangle inequality theorem requires that the sum of any two side lengths must exceed the thi...
Answer: B. the centripetal force upon him is greater than limiting friction
Navigating a circular racing track requires a continuous centripetal force directed toward the curve center. Limiting friction between the tires and road provides the necessary horizontal centripetal force for turning. W...
Answer: A. γ-rays
Gamma rays originate from atomic nuclei during radioactive decay or high-energy nuclear transitions. In contrast, electronic transitions involve electrons shifting between energy levels within atomic shells. Therefore, g...
Answer: B. principal axis
The principal axis is the central line passing through the optical center of a lens, though aperture refers to the effective diameter.
Answer: C. destructive interference
When a wave crest coincides with a trough of another wave, they are completely out of phase. Adding equal crest and trough amplitudes together results in total cancellation of the wave motion. This destructive interferen...
Answer: C. Elements
A mass spectrometer separates ions to determine the mass-to-charge ratio and identify chemical elements and isotopes. Samples must be ionized before entering the spectrometer's electric and magnetic fields. This analytic...
Answer: A. no interference fringes are observed
Producing an optical interference pattern requires two distinct coherent light sources acting simultaneously together. Blocking one of the two slits eliminates the second necessary light source from the experimental setu...
Answer: C. 23.6%
Carnot engine thermal efficiency is calculated using absolute thermodynamic temperatures measured in Kelvin. Converting Celsius temperatures gives source temperature four hundred twenty-three Kelvin and sink temperature...
Answer: D. Resolution of vectors
Vector composition combines multiple separate vectors into a single resultant vector sum. Resolution of vectors takes a single resultant vector and splits it into independent components. Because resolution reverses vecto...
