JEE · Physics doubts
172 doubts found
What is the difference between accuracy and precision?
Accuracy is how close a reading is to the true value; precision is how repeatable your readings are — you can be precise but inaccurate.
What does “Relative velocity” actually mean in Kinematics, and why does it matter for JEE?
the velocity of A as seen from B equals vector v(A) − v(B).
What does “Normal force” actually mean in Laws of Motion, and why does it matter for JEE?
the contact push a surface exerts perpendicular to itself.
What is the difference between conservative force and non-conservative force?
A conservative force (gravity, spring) stores energy recoverably and does path-independent work; a non-conservative force (friction) dissipates energy and depends on the path.
What does “Rolling motion” actually mean in Rotational Motion, and why does it matter for JEE?
combined translation and rotation, so total KE = ½mv² + ½Iω².
What does “Kepler's laws” actually mean in Gravitation, and why does it matter for JEE?
orbits are ellipses; a planet sweeps equal areas in equal times; T² ∝ r³.
What is the difference between isothermal process and adiabatic process?
Isothermal keeps temperature constant (ΔU=0, heat exchanged); adiabatic exchanges no heat (Q=0, temperature changes).
What is the difference between transverse wave and longitudinal wave?
In a transverse wave particles move perpendicular to the wave (light, string); in a longitudinal wave they move along it (sound).
What is the difference between electric field and electric potential?
Field is a vector (force per charge, N/C); potential is a scalar (energy per charge, volts) — field points from high to low potential.
What is the difference between series connection and parallel connection?
In series components share the current and split the voltage; in parallel they share the voltage and split the current.
What is the difference between electric force and magnetic force (on a charge)?
The electric force acts along the field and can do work; the magnetic force acts perpendicular to velocity and does no work.
What does “de Broglie wavelength” actually mean in Modern Physics, and why does it matter for JEE?
every particle has a wavelength λ = h/p, significant only for tiny masses.
What is the difference between fundamental quantities and derived quantities?
Fundamental quantities (length, mass, time…) are defined independently; derived quantities (speed, force…) are built from them.
I keep getting “Relative velocity” questions wrong in Kinematics. What's the trap?
adding speeds as plain numbers instead of subtracting vectors.
I keep getting “Normal force” questions wrong in Laws of Motion. What's the trap?
assuming the normal force always equals mg.
What is the difference between energy and power?
Energy is the total capacity to do work (joules); power is how quickly that work is done (watts).
I keep getting “Rolling motion” questions wrong in Rotational Motion. What's the trap?
counting only translational KE and ignoring the rotational part.
I keep getting “Kepler's laws” questions wrong in Gravitation. What's the trap?
assuming orbital speed is constant — planets move faster near the Sun.
What is the difference between heat and temperature?
Heat is energy in transit due to a temperature difference; temperature measures the average kinetic energy of molecules.
What is the difference between amplitude and frequency?
Amplitude sets the loudness/energy of a wave; frequency sets its pitch/colour.
What is the difference between capacitors in series and capacitors in parallel?
In series the charge is the same and 1/C adds (total C smaller); in parallel the voltage is the same and C adds (total C larger).
What is the difference between EMF and terminal voltage?
EMF is the source's total energy per charge; terminal voltage is the usable voltage after internal-resistance losses.
What is the difference between Faraday's law and Lenz's law?
Faraday's law gives the SIZE of the induced EMF; Lenz's law gives its DIRECTION (opposing the change).
I keep getting “de Broglie wavelength” questions wrong in Modern Physics. What's the trap?
expecting everyday objects to show wave behaviour (their λ is unimaginably small).