Answer:
q₁ = -2.92 nC
Explanation:
Given;
first point charge, q₁ = ?
second point charge, q₂ = 10 nC
net flux through the surface of the sphere, Φ = 800 N.m²/C
According to Gauss’s law, the flux through any closed surface (Gaussian surface), is equal to the net charge enclosed divided by the permittivity of free space.

where;
Φ is net flux
net charge enclosed
ε₀ is permittivity of free space.
= Φε₀
= 800 x 8.85 x 10⁻¹²
= 7.08 x 10⁻⁹ C
= 7.08 nC
q₁ + q₂ = 
q₁ =
- q₂
q₁ = 7.08nC - 10 nC
q₁ = -2.92 nC
Answer:
39225J
Explanation:
Given parameters:
Mass of water = 375grams of water
Change in temperature = 25°C
Specific heat capacity of water = 4.184J/g°C
Unknown:
Amount of heat absorbed = ?
Solution:
To solve this problem, we use the expression below:
H = m c Ф
H is the heat absorbed
m is the mass
c is the specific heat capacity
Ф is the change in temperature
Insert the parameters and solve;
H = 375 x 4.184 x (25) = 39225J
One with greater mass (8kg)
Through the 1/r law, it was concluded that for the sound intensity or pressure is directly proportional to distance or radius. That is,
p = k/r
where k is the proportionality constant. If the distance of a sound wave is quadrupled then, the intensity of the sound is decreased to 1/4 of its original value.