The sentences are invalid and unsound.
<h3><u>Explanation</u>:</h3>
The fire is defined as the vigorous oxidation of a substance. Now oxidation can occur in presence of any oxidising agent. Like magnesium in presence of nitrogen in high temperature with a dazzling brownish flame to produce magnesium nitride. So fire can be produced in absence of oxygen.
Oxygen is present everywhere in world. So production of a whole room without oxygen is very tough to produce and costly process. So its very unsound.
Answer:D) His Facial expressions when they spend time together
Explanation:
Eva's should carefully observe the normal verbal signs by her lover because facial expression gives the hint to listener or viewer that one is interested towards other.
Some common facial Expression are
- Smiling Eyes:While smiling is, of course, an important expression when we speak, attempting to keep a constant smile could make you look more like a trained sociopath than a happy, enthusiastic presenter. These enables other person to feel the good vibes out of you and left a positive impact of your presence.
- Nod on: It is important to express interest in the feedback of your audience. No one likes an identity-centered snob. One way to show that you're actually engaged in the comments and questions they pose is by nodding while you're listening. Moving your head a little wider will help to express your attention as well.
The value of the second charge is 1.2 nC.
<h3>
Electric potential</h3>
The work done in moving the charge from infinity to the given position is calculated as follows;
W = Eq₂
E = W/q₂
<h3>Magnitude of second charge</h3>
The magnitude of the second charge is determined by applying Coulomb's law.

Thus, the value of the second charge is 1.2 nC.
Learn more about electric potential here: brainly.com/question/14306881
Answer:
C. 14400
Explanation:
40min × 6 periods = 240mins total.
1 minute = 60 seconds.
240 minutes × 60 = 14400 seconds.