Answer:
Explanation:
All the rest of the information is extraneous. The only 2 things you have to know are
d = 20 km
t = 8 minutes = 8/60 hours = 0.13333333
So the speed is s = d/t
s = 20/0.1333333 = 150 km/hour
Note: you have not specified what units the speed is. I suppose you could answer 20/8 = 2.5 km/min
When light passes through one transparent medium to another transperent medium it bends and that beding of light is know as refraction of light !
Answer: Resonance in sound is when one object is vibrating at the same frequency to the second object of forces to the second frequency.
Explanation:
"Acoustic resonance is a phenomenon in which an acoustic system amplifies sound waves whose frequency matches one of its own natural frequencies of vibration (its resonance frequencies)." wikipedia I hope this helps you!
Answer:
option (B)
Explanation:
Intensity of unpolarised light, I = 25 W/m^2
When it passes from first polarisr, the intensity of light becomes
Let the intensity of light as it passes from second polariser is I''.
According to the law of Malus
Where, θ be the angle between the axis first polariser and the second polariser.
I'' = 11.66 W/m^2
I'' = 11.7 W/m^2
Any process in which a mixture of materials separates out partially
