Answer:
A hydrometer is an instrument used to determine specific gravity. It operates based on the Archimedes principle that a solid body displaces its own weight within a liquid in which it floats. Hydrometers can be divided into two general classes: liquids heavier than water and liquids lighter than water
Answer:
Part a)

Part b)

Explanation:
As we know that electric force on electric charge is given as

here we have

E = 153 N/C
now force is given as

Gravitational force on electric charge near surface of earth is given as


now the ratio of two forces is given as


Part b)
Now the ball is balanced by the electric force and the force of gravity on it
so here we have



here we have

Answer:
The distance is 1.69 m.
Explanation:
Given that,
First charge 
Second charge 
Distance = 3.25 m
We need to calculate the distance
Using formula of electric field





Put the value into the formula





Hence, The distance is 1.69 m.
Answer:
The observable universe is still huge, but it has limits. because it's most likely like an plane all round.
Explanation: