Neither energy nor matter can enter and exit an isolated system.
Explanation:
There are three types of systems which refers to universe. They are
1. Open System : In an open system, both energy and matter have external interactions. Example:- boiling water in an open pan.
2. Closed system : In a closed system, only energy has interaction with surroundings. Example:- boiling water with a lid on the pan.
3. Isolated system : In an isolated system, neither energy-nor matter has external interactions with surroundings. Example : a thermos flask does not exchange energy and matter.
Hence, the correct option is (a) " neither energy nor matter ".
Answer:
(a) 42°
Explanation:
According to the law of reflection:
Angle of incidence = Angle of reflection
So, angle of reflection = 62°
Angle of incidence = 62°
For refraction,
Using Snell's law as:
Where,
is the angle of incidence ( 62.0° )
is the angle of refraction ( ? )
is the refractive index of the refraction medium (water, n=1.33)
is the refractive index of the incidence medium (air, n=1)
Hence,
Angle of refraction = 
= 42°
