Question:- On a rainy day, small oil films on water show brilliant colours. This is due to A. dispersion B. interference C. diffraction D. polarization
Answer:- Option B
Question:- Materials for rain-proof coats and tents owe their water-proof properties to A. surface tension B. viscosity C. specific gravity D. elasticity
Answer:- Option A
Question:- Sound of frequency below 20 Hz is called A. audio sounds B. infrasonic C. ultrasonic D. supersonics
Answer:- Option B
