NEET · Physics doubts
127 doubts found
What does “Errors in measurement” actually mean in Units, Dimensions & Measurement, and why does it matter for NEET?
absolute error = |measured − true|, relative error = absolute/true, percentage error = relative × 100.
What does “Equations of motion” actually mean in Kinematics, and why does it matter for NEET?
the v=u+at family that connects u, v, a, s and t — valid only for constant acceleration.
What does “Newton's third law” actually mean in Laws of Motion, and why does it matter for NEET?
every action has an equal and opposite reaction, and the two forces act on different bodies.
What does “Conservation of mechanical energy” actually mean in Work, Energy & Power, and why does it matter for NEET?
when only conservative forces act, KE + PE stays constant.
What does “Moment of inertia” actually mean in Rotational Motion, and why does it matter for NEET?
the rotational analogue of mass; it depends on both the mass and how it is distributed about the axis.
What does “Gravitational potential energy” actually mean in Gravitation, and why does it matter for NEET?
for large distances PE = −GMm/r (negative, zero at infinity), not mgh.
What does “Second law of thermodynamics” actually mean in Thermodynamics & Kinetic Theory, and why does it matter for NEET?
heat flows spontaneously from hot to cold, and no engine can be 100% efficient.
What does “Wave motion” actually mean in Oscillations & Waves, and why does it matter for NEET?
a wave transfers energy and momentum through a medium without transporting the medium itself.
What does “Electric potential” actually mean in Electrostatics, and why does it matter for NEET?
the work done per unit charge to bring a charge from infinity to a point, V = kQ/r.
What does “Series and parallel resistors” actually mean in Current Electricity, and why does it matter for NEET?
in series the current is the same and resistances add; in parallel the voltage is the same and 1/R values add.
What does “Lenz's law” actually mean in Magnetism & Electromagnetic Induction, and why does it matter for NEET?
the induced current always opposes the change that produced it, ensuring energy conservation.
What does “Bohr model” actually mean in Modern Physics, and why does it matter for NEET?
electrons occupy quantised orbits; for hydrogen E_n = −13.6/n² eV.
I keep getting “Errors in measurement” questions wrong in Units, Dimensions & Measurement. What's the trap?
mixing up accuracy (closeness to the true value) with precision (repeatability).
I keep getting “Equations of motion” questions wrong in Kinematics. What's the trap?
using them when acceleration is changing.
I keep getting “Newton's third law” questions wrong in Laws of Motion. What's the trap?
thinking action and reaction cancel out — they can't, because they act on different objects.
I keep getting “Conservation of mechanical energy” questions wrong in Work, Energy & Power. What's the trap?
applying it when friction or other non-conservative forces are present.
I keep getting “Moment of inertia” questions wrong in Rotational Motion. What's the trap?
treating it as a fixed property regardless of the axis chosen.
I keep getting “Gravitational potential energy” questions wrong in Gravitation. What's the trap?
using mgh far from the surface, where it no longer holds.
I keep getting “Second law of thermodynamics” questions wrong in Thermodynamics & Kinetic Theory. What's the trap?
believing you can fully convert heat into work in a cycle.
I keep getting “Wave motion” questions wrong in Oscillations & Waves. What's the trap?
thinking the particles travel along with the wave.
I keep getting “Electric potential” questions wrong in Electrostatics. What's the trap?
thinking zero field means zero potential (or vice versa).
I keep getting “Series and parallel resistors” questions wrong in Current Electricity. What's the trap?
adding parallel resistances directly instead of their reciprocals.
I keep getting “Lenz's law” questions wrong in Magnetism & Electromagnetic Induction. What's the trap?
getting the direction of induced current backwards.
I keep getting “Bohr model” questions wrong in Modern Physics. What's the trap?
using a positive energy for a bound electron — bound states are negative.