It is a completely false statement that in <span>any energy transformation, there is always some energy that gets wasted as non-useful heat. The correct option among the two options that are given in the question is the second option. I hope that this is the answer that has actually come to your desired help.</span>
Explanation:
(a)
Critical angle is the angle at the angle of refraction is 90°. After the critical angle, no refraction takes place.
Using Snell's law as:
Where,
is the angle of incidence
is the angle of refraction = 90°
is the refractive index of the refraction medium
is the refractive index of the incidence medium
Thus,
The formula for the calculation of critical angle is:
Where,
is the critical angle
(b)
No it cannot occur. It only occur when the light ray bends away from the normal which means that when it travels from denser to rarer medium.
Answer:
Work done W =1406.25 J
Explanation:
Work done on a body can be calculated using newton's 2nd laws:
F=ma
Hence acceleration of the block is given by:
Displacement of the object is given by:

Substitute the values
Now work done is given by:
W=F.S
W = 25×56.25
W =1406.25 J
Answer: The Earth and you are attracted to the centers of each other by a pair of equal gravitational forces. The size of the force attracting you toward the center of the Earth is your "weight" on Earth. The size of the force attracting the Earth toward the center of you is the Earth's "weight" on you.
Explanation: