Answer: C and D
Explanation: One of the first rule for total internal reflection to occur is that the ray must move from a dense to a less dense medium, hence refractive index of medium a must be greater than that of b.
When a ray moves from a dense to a less dense medium, the refracted ray moves away from the normal thus increasing the size of the angle of refraction (total internal refraction occurs when the angle of refraction is 90° and the angle of incidence at this point is known as the critical angle), hence the angle of incidence must be greater than the critical angle.
These points verifies option C and D
Answer:

Explanation:
Time can be found by dividing the distance by the speed.

The distance is 45 meters and the speed is 12.5 meters per second.


Divide. Note that the meters, or "m" will cancel each other out.


It will take the dolphin 3.6 seconds to swim a distance of 45 meters are 12.5 meters per second.
Answer:
2 kg
Explanation:
Remember:
F = m * a re-arrange to
F/a = m substitute in the given values
10 / 5 = 2 kg
In some early mornings , dew drops can be found on grass or a car parked outside, but not on other materials such as the sidewalk because the night -time temperature on grass and the car went below the dew point, but the temperature of the concrete did not drop enough to reach the dew point level
Dew can be formed on any object when the temperature of the object drop. When this happen, the object will be cool which will eventually cool the surrounding air around the object.
Dew drops is as a result of condensation in the air. When the cool air causes the air vapor to convert to liquid. The dew will form when the temperature of the object balances with the dew point in the surrounding environment.
In some early mornings , dew drops can be found on grass or a car parked outside, but not on other materials such as the sidewalk because the night -time temperature on grass and the car went below the dew point, but the temperature of the concrete did not drop enough to reach the dew point level
Therefore the correct option is therefore A
Learn more here : brainly.com/question/13834972