Answer:
when the water is heated with immersion heater, the water becomes less dense due to which the warm water rises up and the cooler water fills it's space.
Answer: The Bluray Disk can store more information
The wavelenght of red light is around 700nm, whereas the wavelenght of violet light is around 400nm. Since the violet light has smaller wavelenght the data tracks on a Blu-ray Disk can be spaced closer together and the Blueray Disk can store more information
Explanation: Because a disk work by storing data using bits, the more bits can be stored in one place improves the total storage on the unit. The less the space to storage the bit, the more space overall for the disk.
To solve the problem it is necessary to refer to the definition of entropy.
Entropy is defined aso
Where,
Heat exchange
T = Temperature
Since the heat exchange is conserved and it is an isothermal process where the temperature remains constant the change in entropy remains the same, ie 
(Reamins same)
Therefore the correct answer is C.
because its has energy and uses it natural energy from the ground
