Answer: Option (a) is the correct answer.
Explanation:
AC current stands for alternating current. In an alternating current there is periodically reverse movement of current.
This means electrons move in one direction for a certain time and then they reverse their movement for the same time period and it continues in the back and forth position.
Thus, we can conclude that the statement electrons move back and forth is true regarding AC current.
The correct answer for the question that is being presented above is this one: "a. the wavelength of light emitted by the star." The mass of a star can be determined by studying <span>the wavelength of light emitted by the star. It also has something to do with the gravitational force that it exerts.</span>
Answer:B
Explanation:
Initial velocity, u=0m/s
Distance,s=20m
a=+g=9.8m/s*s
Using v*v=u*u+2gs
v*v=0+2*9.8*20
v*v=392
v=19.8
When s=20m, v = 19.8m/s
Therefore when v = 10m/s, s= 10*20/19.8
s =10.1m
Igneous rock your welcome
