Answer:
E_total = 1.30 10¹⁰ C / m²
Explanation:
The intensity of the electric field is
E = k q / r²
on a positive charge proof
The total electric field at the midpoint is
as q₁= 6 10⁻⁶ C the field is outgoing to the right
for charge q₂ = -3 10⁻⁶ C, the field is directed to the right, therefore
E_total = E₁ + E₂
E_total = k q₁ / r₁² + k q₂ / r₂²
r₁ = r₂ = r = 4 10⁻² m
E_total = k/r² (q₁ + q₂)
we calculate
E_total = 9 10⁹ / (4 10⁻²)² (6.0 10⁻⁶ +3.0 10⁻⁶)
E_total = 1.30 10¹⁰ C / m²
The amount of heat needed to increase the temperature of a substance by

is given by

where
m is the mass of the substance

the specific heat capacity

the increase in temperature
In our problem, the mass of the water is m=750 g, the specific heat is

and the amount of heat supplied is

, so if we re-arrange the previous formula we find the increase in temperature of the water:
The right answer is B. hope this helps you :)
Usually, it increases the solubility in water.
A high tide means when the water has risen and is higher up(closer to high up land). Low tide is when it’s receded