Answer:
The correct option is A
Explanation:
Water from a river is used for many activities in a community. These activities could include (but not limited to) tourism, drinking for animals, local transport, irrigation for nearby farming, recreation (as in swimming), habitat for some living organisms among others. Rivers are not limited by what limits the influence of oceans such as taste (it's saltiness, which cannot be used in farming also) and wave current.
Answer: Option D is correct.
Explanation: Equation given by de Broglie is:
![\lambda =\frac{h}{mv}](https://tex.z-dn.net/?f=%5Clambda%20%3D%5Cfrac%7Bh%7D%7Bmv%7D)
where,
= wavelength of the particle
h = Planck's constant
m = mass of the particle
v = velocity of the particle
In option A, football will have some mass and is moving with a velocity of 25 m/s, hence it will have some wavelength.
In Option B, unladen swallow also have some mass and is moving with a velocity of 38 km/hr, hence it will also have some wavelength.
In Option C, a person has some mass and is running with a velocity of 7 m/hr, hence it will also have some wavelength.
As, the momentum of these particles are large, therefore the wavelength will be of small magnitude and hence, is not observable.
From the above, it is clearly visible that all the options are having some wavelength, so option D is correct.
Answer:
176.7996 grams
Explanation:
Molar mass of Cobalt is 58.9332g. 58.9332 *3 is 176.7996g.
The concentration of solution in M or mol/L can be calculated using the following formula:
.... (1)
Here, n is number of moles and V is volume of solution in L.
The molecular formula of potassium sulfate is
thus, there are 2 moles of potassium in 1 mol of potassium sulfate.
1 mol of potassium will be there in 0.5 mol of potassium sulfate.
Mass of potassium is 4.15 g, molar mass is 39.1 g/mol.
Number of moles can be calculated as follows:
![n=\frac{m}{M}](https://tex.z-dn.net/?f=n%3D%5Cfrac%7Bm%7D%7BM%7D)
Here, m is mass and M is molar mass
Putting the values,
![n=\frac{(4.15 g}{(39.1 g/mol}=0.1061 mol](https://tex.z-dn.net/?f=n%3D%5Cfrac%7B%284.15%20g%7D%7B%2839.1%20g%2Fmol%7D%3D0.1061%20mol)
Thus, number of moles of
will be
.
The volume of solution is 225 mL, converting this into L,
![1 mL=10^{-3}L](https://tex.z-dn.net/?f=1%20mL%3D10%5E%7B-3%7DL)
Thus,
![225 mL=0.225 L](https://tex.z-dn.net/?f=225%20mL%3D0.225%20L)
Putting the values in equation (1),
![C=\frac{(0.053 mol}{0.225 L}=0.236 M](https://tex.z-dn.net/?f=C%3D%5Cfrac%7B%280.053%20mol%7D%7B0.225%20L%7D%3D0.236%20M)
Therefore, concentration of potassium sulfate solution is 0.236 M.