Answer:
7.71 V
Explanation:
When the charge remains constant, the potential difference decrease by the factor of the dielectric constant K
V new = V initial / K = 12 V / 2.8 = 4.29 V
ΔV ( change in potential) = V initial - V new ( after dielectric has been added) = 12 V - 4.29 V = 7.71 V
The potential difference decreases by 7.71 V
Citric Acid is the correct answer because it contains a density of 1.66 g/cm3, whereas water= 1.00 g/cm3, Olive oil= 0.93 g/cm3, Ethyl alcohol= 0.79 g/cm3
Answer:

Explanation:
Given,
mass = 1.41 g = 0.00141 Kg
Electric field,E = 670 N/C.
We know,
Force in charge due to Electric field.
F = E q
And also we know
F = m g
Equating both the equation of motion
m g = E q

Charge of the particle is equal to 
Answer: 1 dioptre of power of a lens is defined as the unit of measuring the power of optical lens Or curved mirror which is equal to the reciprocal of the focal length. The focal length is measured in the meter. 1 dioptre is equal to 1/m where m is the focal length. Basically dioptre is the SI unit of optical power of the lens.