Answer:
reference against doubt
Explanation:
exact standards of measurement are a reference point for situations in doubt , a line against which to test and observe.
The ability of singers to shatter glass is due to the control of frequency in their voices. The sound waves will vibrate the air particles that surround the glass at its resonant frequency. The glass will break if a singer sings too loudly.
The ancient Greeks, in a theory that was suggested around 450 BC, believed that everything was from from four elements. These elements included earth, water, air and fire. Later, Aristotle supported this theory.
Therefore, the first option is correct.
Answer:
F = 3.15 N
Explanation:
Given electric charge, q = 6.3 μC
The magnitude of electric field, 
We need to find the electric force on the charge due to the electric field. The electric force is given by :
F = qE
Putting all the values,
So, the required force on the charge is 3.15 N.
