Answer:
a. reflection of all the light at a surface.
Explanation:
When light rays passing from the denser medium to the rarer medium and the angle of incidence is greater than the critical angle, the refraction of light does not take place and the incident ray is totally reflected back into the denser medium. This phenomenon is called total internal reflection.
There are two conditions that need to be fulfilled in order for the total internal reflection to take place:
1. The ray of light should be incident from denser to rarer medium.
2. The angle of incidence should be greater than the critical angle.
Therefore, the correct option will be:
<u>a. reflection of all the light at a surface.</u>
Answer:7.93 m/s
Explanation:
Given
mass of ball 
Mass of hanging ball 
Length of string 
Maximum angle turned 
is the initial velocity of ball 1 and 0 is the initial velocity of ball 2
For Perfectly elastic final velocity of ball 1 and 2 is given by


where
and
are the velocity of 1 and 2 before collision
thus 



By energy conservation on second ball we get
Kinetic energy=Potential Energy




thus 
Make prediction about what will happen certain circumstances
Answer:
Time = 4.1 s
Explanation:
Momentum = mv = (12000)(4.25) = 51000 kg m/s
Momentum = Impulse (mv = ft) so
51000 = (9200)t
t = (51000)/(9200) = 5.54 seconds
Impulse of the current and the engine must equal so (ft = ft)
51000 = (12500)t
t = (51000)/(12500) = 4.08
But accounting for significant figures, time equals 4.1 seconds
If one of two interacting charges is doubled, the force between the charges will double.
Explanation:
The force between two charges is given by Coulomb's law

K=constant= 9 x 10⁹ N m²/C²
q1= charge on first particle
q2= charge on second particle
r= distance between the two charges
Now if the first charge is doubled,
we get 
F'= 2 F
Thus the force gets doubled.