relation between potential difference and electric field is given as

so here we know that
d = 3 cm



So now when plates are separated to 4 cm distance carefully
the potential difference between them will change but the electric field between them will remain constant
So at distance of 4 cm also the electric field will be E = 1000 N/C
Answer:
12N to the right.
Explanation:
There is a force of 12N upwards and a force of 12N downwards: these cancel out.
Assign a negative value to forces towards the left, and a positive value to the forces towards the right: -3N and +15N
Combine them: -3N+15N = 12N
The net force has a magnitude of 12N, and since our answer was positive, it acts towards the right.
The lithosphere because it includes the outer region of the earth including the crust and outer mantle
Explanation:
Compounds are substances composed of two or more kind of atoms or elements joined together in a definite grouping. The properties of compounds are distinct from those of the individual elements that are combined in its make up.
There are several millions of compounds that are known. Compounds are derived from elements. They are usually represented by chemical formulae.