Answer: Option D is correct.
Explanation: Equation given by de Broglie is:
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:
the answer is B-2nd; stars
Explanation:
Answer: The metal that has a greater reactivity is more easily oxidized.
Explanation:
Oxidation is when the elements lose electrons and increase their oxidation state.
The metals tend to react by losing electrons and form the corresponding cation.
For expample, sodium (an alkalyne metal) loses one elecron and form the cation Na¹⁺ , then this cation combine with an anion and form compounds like NaCl, NaOH. The same do the other alkalyne metals.
Magnesium (an alkalyne earth metal) loses two electrons and form the cation Mg²⁺, then it combines with some anions to form compounds, like MgSO₄, Mg(OH)₂.
So, the easier the metal gets oxidized the greater its reactivity.
Answer:
A and B is the answer as there structure change
C. a change of state. It can be a physical or a chemical state of change.
