The correct answer is b. negative reinforcement. Since Elton followed his mother to stop her from nagging, it is called negative reinforcement. Had she used other ways to persuade him to study, it would be a positive reinforcement. Thank you for posting your question. I hope that this answer helped you. Let me know if you need more help.
Answer:
Covalent bonding
Explanation:
Covalent bonding is the type of bonding found in all molecular substances much as water, carbon dioxide or methane. Unlike ionic bonding which is found in ionic substances, covalent bonding involves sharing, not transfer, of electrons between the bonding atoms to form molecules.
The correct answer of the question is : 0.001 s.
CALCULATION:
As per the question, the speed of sound v = 330 m/s
The frequency of the sound f = 990 Hz.
Let the wavelength of the wave is .
The wavelength of the wave is calculated as-
wavelength
=
= 0.33 m.
Now we are asked to calculate the time period.
The time period of the wave is reciprocal of frequency.
Mathematically time period T =
=
= 0.001 s.
As per the question, we need the period.
Hence, the period of the wave is 0.001 s.
Basically it is the difference in velocity divided by the time it takes to make that change.