Answer:

Explanation:
The difference of electric potential between two points is given by the formula
, where <em>d</em> is the distance between them and<em> E</em> the electric field in that region, assuming it's constant.
The electric field formula is
, where <em>F </em>is the force experimented by a charge <em>q </em>placed in it.
Putting this together we have
, so we need to obtain the electric force the charged ball is experimenting.
On the second drop, the ball takes more time to reach the ground, this means that the electric force is opposite to its weight <em>W</em>, giving a net force
. On the first drop only <em>W</em> acts, while on the second drop is <em>N</em> that acts.
Using the equation for accelerated motion (departing from rest)
, so we can get the accelerations for each drop (1 and 2) and relate them to the forces by writting:


These relate with the forces by Newton's 2nd Law:


Putting all together:

Which means:

And finally we substitute:

Which for our values means:

During a phase change, the temperature remains constant. obviously all the heat is used in phase transformation.
The specific gravity is how the density of the object compares to the density of water. Water's density is 1gram per milliliter. We just need to figure out the density of the object.
The object is .8 kg and it displaces 500mL of water, so the density is the mass divided by the volume. Since the density of water is given in grams, we have to convert the objects mass from kg to g and then we can get the density.
.8kg * 1000g/kg = 800 grams
So
800g/500ml = 1.6grams/mL this is the density.
So divide the density of your object by the density of water, which is 1g/mL, you get 1.6 as the specific gravity. This means the object is 1.6 times more dense than water.
Answer:

Explanation:
The relationship between the refractive index and the critical angle is given as follows:

where,
η = refractive index = 1.67
θc = critical angle =?
Therefore,

