The electrostatic energy stored in a capacitor with capacitance

, with a voltage difference V applied to it, and without dielectric, is given by

Now let's assume we fill the space between the two plates of the capacitor with a dielectric with constant k. The new capacitance of the capacitor is

So, the energy stored now is

Therefore, the ratio between the energies stored in the capacitor before and after the introduction of the dielectric is
Answer:
ΔH°comb=-5899.5 kJ/mol
Explanation:
First, consider the energy balance:
Where
is the calorimeter mass and
is the number of moles of the samples;
is the combustion enthalpy. The energy balance says that the energy that the reaction release is employed in rise the temperature of the calorimeter, which is designed to be adiabatic, so it is suppose that the total energy is employed rising the calorimeter temperature.
The product
is the heat capacity, so the balance equation is:

So, the enthalpy of combustion can be calculated:

I will be happy to solve any doubt you have.
"Three short blasts" sound signal alerts others when a boat is backing up based on the boating safety rule. The short blast is a sound which has one second period, thus three short blasts mean three of this kind of sound. The sound signal is used for alerting anything surrounding the boat to avoid a collision.
<span>Answer:
skater x km/h
cyclist 20 faster x + 20 km/h
skater 30 km
cyclist 80 km
skater time = cyclist time
t=d/r
30 / x = 80 /( x + 20
cross multiply
30 ( x + 20 ) = 80 x
30 x + 600 = 80 x
30 x - 80 x = -600
-50 x = -600
/ -50
x = 12 km/h
12 km/h skater</span>
Answer:
Distance will be 
Explanation:
We have given that Buffalo has a latitude of 42.9°N
And Raleigh has a latitude of 35.8°N
Radius of the earth = 3960 miles
We have to calculate the distance between given two cities
Difference in their latitudes = 
Now changing the angle in radian = 
So distance will be 