ECAT MCQs

Refractive index indicates how strongly a medium slows light.
It is dimensionless.

Snell's law is n1 sinθ1 = n2 sinθ2.
It predicts the bending of a ray at an interface.

Beyond the critical angle, no transmitted ray propagates into the lower-index medium.
All light is reflected internally.

Wavelength may be measured between adjacent crests or compressions.
It is related to speed and frequency.

For a spring oscillator, ω=√(k/m).
√(200/0.5)=√400=20 rad/s.

Wave speed depends on the medium for mechanical waves.
It equals frequency times wavelength.

When waves overlap, their displacements add.
Constructive interference reinforces, while destructive interference reduces amplitude.

Diffraction is strongest when the opening or obstacle is comparable to wavelength.
It is a general wave property.

Standing waves form from superposition of opposite traveling waves.
Nodes remain at zero displacement.

Higher-frequency sound is perceived as higher pitch.
Pitch perception is related to but not identical with frequency.

Greater wave amplitude generally means greater intensity.
Perceived loudness is also frequency-dependent.

Approach raises observed frequency, while separation lowers it.
The effect occurs for sound and electromagnetic waves.