Answer:
It can occur only when light is incident on an interface where the index of refraction on the other side is less.
Explanation:
When the light passes from a denser medium, with refractive index n1, to another less dense medium, with refractive index n2, the incident light beam is refracted in such a way that it is not able to cross the surface between both media, the light beam is fully reflected and completely confining in the optically denser medium through which it propagates. For this phenomenon to occur, it is necessary that the angle of the incident light beam with respect to the normal be greater than or equal to the critical incidence angle θc. The critical angle can be calculated as :

Answer:
the branch of mechanics concerned with the motion of objects without reference to the forces which cause the motion.
Answer:
2.12m/s
Explanation:
Given parameters:
Force on trolley = 1.5N
Mass of trolley = 0.2kg
Unknown:
Velocity of the trolley = ?
Solution:
To solve this problem, we first find the acceleration of the trolley;
Force = mass x acceleration
Acceleration =
Insert the parameters and solve;
Acceleration =
= 7.5m/s²
Now to find the acceleration;
Initial velocity = 0m/s
v² = u² + 2aS
v is the final velocity
u is the initial velocity
a is the acceleration
S is the distance
Distance = 30cm and this is 0.3m
v² = 0² + 2(7.5)0.3 = 4.5
v = √4.5 = 2.12m/s
The answer would be D , the rest are ways humans basically destroy nature
Actual Mechanical Advantage(AMA) = Weight / Force
Here, Weight = 764 N
Force = 255 N
Substitute the values in to the expression,
AMA = 764 / 255
AMA = 2.99
After rounding-off to the nearest tenth value, it would be 3
Finally, option C would be your answer.
Hope this helps!