Answer:

Explanation:
Given:
- mass of water,

- initial temperature of water,

- initial temperature of pan,

- mass of pan,

- mass of water evapourated,

- specific heat of water,

- specific heat of aluminium pan,

- latent heat of vapourization,

<u>Using the equation of heat:</u>
<em>Here, initially certain mass of water is vapourised first and then the remaining mass of water comes in thermal equilibrium with the pan.</em>



Answer:
A) Its density will decrease
Explanation:
When an object is heated, its volume increases. This is due to the fact that the particles in the medium vibrate more (if it is a solid) or they move more (if it is a liquid or a gas), therefore they tend to occupy a larger space.
At the same time, the mass of the object does not change, because the mass just represents the amount of matter contained in the object, so it does not increase/decrease at different temperatures.
The density of an object is defined as the ratio between the mass (m) and the volume (V):

We said that the mass remains unchanged while the volume increases: since the density is inversely proportional to the volume, this means that the density decreases.
Answer:
3a, 2b,4c,1d
Explanation:
what do I need to explain just something you know
Mechanical Energy transforms into Thermal due to the moving parts rubbing on eachother creating heat and friction.
Answer: a. 53cm b. Diverging c. 0.02dioptres
Explanation:
Since the person in question cannot see far object clearly, it shows that the individual is suffering from myopia (short sightedness).
If the object distance (u) is 53cm. for the person to be able to see far way, it means the image must be at infinity. This shows image distance v is infinity. Using the lens formula
1/f = 1/u+1/v
1/f = 1/53 + 1/Infinity
1/f = 1/53 + 0
f=53cm
b) The lens used is concave lens (diverging lens) to diverge all rays outwards
c) Power of a lens P will be 1/53.
P = 0.02dioptres