Answer:
One when it enters the glass slab from air and second time when it enters the air through glass slab. When light rays travelling through air enters glass slab, they get refracted and bend towards the normal. Now the direction of refracted ray changes again when it comes out of the glass slab into air.
Answer:
The force required to maintain an object at a constant velocity in free space is equal to Zero.
Red, Orange, Yellow, Green, Blue, Indigo, Violet.
Remember ROYGBIV.
Answer:

Explanation:
Given that
Temperature of warm water ,T₁ = 25 °C
Temperature of cold water ,T₂ = 5 °C
The maximum possible efficiency of any heat is will be same as the efficiency of the Carnot heat engine.Therefore the maximum efficiency of OTEC system is given as follows
T should be Kelvin scale
Now by putting the values


Therefore the maximum efficiency will be 0.067 or 6.7%.