Weeds are very important agronomically because they reduce the yield of crops in three ways: by competing with the crop for water, light and nutrients, by interfering with crop harvest, and by contaminating harvested products with weed seeds and toxins. Weeds can reduce yield up to 50% and are responsible for millions of dollars in crop losses each year.
It’s biotic factor would be competition as Competition can be defined as an interaction between organisms or species, in which the fitness of one is lowered by the presence of another.
Answer:
R= 20 ohm
Explanation:
Given that
Current ,I = 6 A
Voltage difference ,ΔV = 120 V
Lets take resistance of the stem iron = R
We know that ,the relationship between current ,voltage difference and resistance is given as
ΔV = I R
Now by putting the values in the above equation we get
R= 20 ohm
Therefore the resistance of the steam will be 20 ohm.
“Charged objects have an imbalance of charge - either more negative electrons than positive protons or vice versa. And neutral objects have a balance of charge - equal numbers of protons and electrons. The principle stated earlier for atoms can be applied to objects. Objects with more electrons than protons are charged negatively; objects with fewer electrons than protons are charged positively.
In this discussion of electrically charged versus electrically neutral objects, the neutron has been neglected. Neutrons, being electrically neutral play no role in this unit. Their presence (or absence) will have no direct bearing upon whether an object is charged or uncharged. Their role in the atom is merely to provide stability to the nucleus.”
Hope this helps a bit.
!! (Credits to The Psychics Classroom) !!
Answer:
Option (A) , (b) and (d) are correct option
Explanation:
According to Coulomb's law electric force between two charges is given by
From the relation we can say that force is directly proportional to magnitude of charges and inversely proportional to distance between them '
So if we increase the distance then force will decrease
Increase if any of the charge get larger
If force is attractive then both the charge will be of different sign and is force is repulsive then both the charges of same sign
From above conclusion we can say that (a), (b) and (d) are correct option
