Answer:
A. a material burns out when current is excessive
Answer:
t=1.623 sec
Explanation:
The distance traveled before the echo is had is:

Given the speed of sound as v=345m/s, we use the speed equation to solve for t:

Hence, it takes 1.623 seconds to hear the echo.
Waterfalls are created when a river flows following a descending rapid slope. The waterfall, then, flows from the source (where it starts) to the mouth (where it ends).
Waterfalls are created when the erosion of the rocks at the bottom of the slope is more powerful than the erosion of the rocks on the top.
After many years the water is able to erode the rocks on the top as well, and the waterfall slowly disappears.
Therefore the options that apply are:
b) waterfalls move towards their mouth;
c) the top or cap rock is resistant to erosion;
<span>f) waterfalls indicate a youthful river </span>
Answer:
a) 3.33 ns
b) Water distance = 0.75 m
Glass distance = 0.66 m
Diamond distance = 0.41 m
Explanation:
We take the speed of light, c = m/s.
Speed = distance/time
Time = distance/speed
a)

t = 3.33 ns
b)
Refractive index, n = speed of light in vacuum / speed of light in medium





Thus, the distance traveled in the same time is numerically equal to the reciprocal of the refractive index.
For water n = 1.333
d = 1/1.333 = 0.75 m
For glass n = 1.517
d = 0.66 m
For diamond n = 2.417
d = 0.41 m