16) The depth of pond is ....... if it seems to be 10m a) 10m b) 7.7m c) 13.3m d) 20m
1 answer:
The answer is d) 20 m.
The depth of pond is 20 m if it seems to be 10 m.
The formula relating real depth and app. depth :
In this case, refractive index has to be an whole number for real depth to give a whole number for app. depth.
- Then, real depth must be a multiple of 10, but refractive index cannot be 1
- The option is 20 m
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Answer: 2. Solution A attains a higher temperature.
Explanation: Specific heat simply means, that amount of heat which is when supplied to a unit mass of a substance will raise its temperature by 1°C.
In the given situation we have equal masses of two solutions A & B, out of which A has lower specific heat which means that a unit mass of solution A requires lesser energy to raise its temperature by 1°C than the solution B.
Since, the masses of both the solutions are same and equal heat is supplied to both, the proportional condition will follow.
<em>We have a formula for such condition,</em>
.....................................(1)
where:
= temperature difference
- Q= heat energy
- m= mass of the body
- c= specific heat of the body
<u>Proving mathematically:</u>
<em>According to the given conditions</em>
- we have equal masses of two solutions A & B, i.e.
- equal heat is supplied to both the solutions, i.e.
- specific heat of solution A,
- specific heat of solution B,
&
are the change in temperatures of the respective solutions.
Now, putting the above values
Which proves that solution A attains a higher temperature than solution B.