B. base
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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:
D. The piece of bread travels with straight- line horizontal acceleration.
Explanation
In the given question according to the information the process of polymerization is an addition polymerization.
<h3>What is polymerization?</h3>
Polymerization is a process in which addition of many small molecules takes place for the formation of a large three dimensional substance known as polymer.
In the polymerization of polyethene the small repeating molecule is ethene and in this process product formed due to the addition process to the double bond of the ethene.
- In condensation polymerisation removal of water molecule or any other molecule takes place.
- In dehydrogenation polymerisation removal of hydrogen molecule takes place.
- In dehydrohalogenation polymerisation removal of hydrogen halide molecule takes place.
Hence given process is an addition polymerisation.
To know more about polymerisation, visit the below link:
brainly.com/question/17932602
