JEE · Physics · Oscillations & Waves doubts
14 doubts found
What does “Simple harmonic motion” actually mean in Oscillations & Waves, and why does it matter for JEE?
oscillation where the restoring force is proportional to and opposite the displacement, F = −kx.
I keep getting “Simple harmonic motion” questions wrong in Oscillations & Waves. What's the trap?
assuming every back-and-forth motion is SHM.
What does “Time period of a pendulum” actually mean in Oscillations & Waves, and why does it matter for JEE?
T = 2π√(L/g) — it depends on length and gravity, not on mass or (small) amplitude.
I keep getting “Time period of a pendulum” questions wrong in Oscillations & Waves. What's the trap?
thinking a heavier bob swings with a different period.
What does “Wave motion” actually mean in Oscillations & Waves, and why does it matter for JEE?
a wave transfers energy and momentum through a medium without transporting the medium itself.
I keep getting “Wave motion” questions wrong in Oscillations & Waves. What's the trap?
thinking the particles travel along with the wave.
What does “Beats” actually mean in Oscillations & Waves, and why does it matter for JEE?
the slow throbbing when two close frequencies superpose; beat frequency = |f₁ − f₂|.
I keep getting “Beats” questions wrong in Oscillations & Waves. What's the trap?
adding the frequencies instead of subtracting.
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 amplitude and frequency?
Amplitude sets the loudness/energy of a wave; frequency sets its pitch/colour.
What is the difference between mechanical wave and electromagnetic wave?
Mechanical waves need a medium (sound); electromagnetic waves (light) travel through vacuum.
When do I use T = 2π√(m/k) in Oscillations & Waves, and what does it mean?
period of a mass on a spring.
When do I use T = 2π√(L/g) in Oscillations & Waves, and what does it mean?
period of a simple pendulum.
When do I use v = fλ in Oscillations & Waves, and what does it mean?
wave speed equals frequency times wavelength.