Answer:
Explanation:
From the question we are told that
Distance b/w plate 
P_1 Potential at 7.35 
Generally the equation for electric field at a distance is mathematically given as
This can be solve using the formula P = I^2 * Rwhere P is the powerI is the CurrentR is the resistanceP = I^2 * R
1/4 Watt = I^2 * 100 ohm solve for II^2 = 1/400 I = 0.05 amps then using the formula to solve for the voltage:V = I * RV = 0.05 amps * 100 ohms V = 5 volts
No the density does not change. Density is a ratio D=m/v no matter how much of a substance you have its mass will be proportional.
When doing density labs sometimes you might get different answers due to errors that are unavoidable.