Waves

Total internal reflection occurs only when the angle of incidence in the optically denser medium exceeds the critical angle, preventing any light from refracting out. Option C is incorrect because at angles below the critical angle, most of the light refracts into the second medium instead of reflecting.

Diffraction is most pronounced when the size of the gap or obstacle is comparable to the wavelength of the passing wave, causing significant spreading. Option A is incorrect because if the slit is much larger than the wavelength, the wave passes through with minimal spreading, creating a clear shadow.

Because wave speed remains constant, frequency and wavelength are inversely proportional. A diagram for this topic isn't available yet — the worked example below walks the same reasoning step by step.

• !Option A is incorrect because doubling both frequency and wavelength would quadruple the wave speed.
• !Option C is incorrect because at angles below the critical angle, most of the light refracts into the second medium instead of reflecting.
• !Option A is incorrect because if the slit is much larger than the wavelength, the wave passes through with minimal spreading, creating a clear shadow.
• !Option A is incorrect because constructive interference requires waves to arrive in phase, where peaks align with peaks to reinforce the signal.

Answer each from memory — you'll see instantly whether you're right and why.

Run a focused 10-question mini-mock on Waves and see it stick.