Answer:
Explanation:
Electric field due to a point charge Q at a point at distance d is given by the relation
E = 
Since Q1 and Q2 are of the same magnitude and distance , so they will create eletric field of same magnitude. Similarly field due to rest of the charges will also be same.
The charges are situated on the corners of a square in such a way that
equal charges of Q1 and Q3 are situated on the diametrically opposite corners of the square. Fields due to these two charges will be equal and opposite in direction. Therefore net field due to these two charges will be zero.
On the same ground, we can say that field due to Q2 and Q4 at the centre will be equal and opposite and therefore they will cancel out each other. Net field at the centre will be zero
Overall, net field due to all the four charges will be zero
Answer:
A: Sound waves produce an echo
Explanation:
because the cup is a hard smooth surface you can hear the voice
Change in color
Change in color is a physical reaction
The <span> behaviors will help keep her and her co-workers safe are:
</span><span>- Be familiar with her employer’s workplace violence policy. (so they could operate within the safety guideline)</span>
<span>-. Report any warning signs or threats of violence. (better be cautious than sorry)</span>
<span>- Treat co-workers and customers with respect.(to prevent any potential conflicts that could lead to violence)</span>
Answer:
over harvesting, pollution, introduction of invasive species such as new predators and food competitors
Explanation:
The main cause of mass extinction is Humans cause extinction of a species through overharvesting. The second main cause is pollution ., introduction of invasive species such as new predators and food competitors, habitat destruction, overhunting and other influences. Another very important cause of mass extinction is the unsustainable human population growth.
The five mass extinction events are
Ordovician Mass Extinction
Devonian Mass Extinction
Permian Mass Extinction
Triassic -Jurassic Mass Extinction
and Cretaceous -Tertiary (or the K-T) Mass Extinction.