Answer:

is the no. of electrons
Explanation:
Given:
- quantity of charge transferred,

<u>No. of electrons in the given amount of charge:</u>
As we have charge on one electron 
so,


is the no. of electrons
- Now if each water molecules donates one electron:
Then we require
molecules.
<u>Now the no. of moles in this many molecules:</u>

where
Avogadro No.


- We have molecular mass of water as M=18 g/mol.
<u>So, the mass of water in the obtained moles:</u>

where:
m = mass in gram


Answer:
C
Explanation:
To melt the alcohol
Heat needed = M . L = 2 . 25 = 50 kcal
To warm up the alcohol
Heat needed = M . sp. ht. . ∆t = 2 . 0.6 . 100 = 120 kcal
Total heat needed = 170 kcal
Assuming that 0.6 kcal/ kg / ˚C is the specific heat and that the answer is wanted in kcal ( a rather odd unit to be in use here.)
Answer:
is the distance from the obstacle of reflection.
wavelength 
Explanation:
Given that:
- frequency of sound,

- time taken for the echo to be heard,

- speed of sound,

We know,

<em>During an echo the sound travels the same distance back and forth.</em>


is the distance from the obstacle of reflection.
<u>Now the wavelength of sound waves:</u>



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