Answer:

Explanation:
A charge located at a point will experience a zero electrostatic force if the resultant electric field on it due to any other charge(s) is zero.
is located at the origin. The net force on it will only be zero if the resultant electric field intensity due to
and
at the origin is equal to zero. Therefore we can perform this solution without necessarily needing the value of
.
Let the electric field intensity due to
be +
and that due to
be -
since the charge is negative. Hence at the origin;

From equation (1) above, we obtain the following;

From Coulomb's law the following relationship holds;

where
is the distance of
from the origin,
is the distance of
from the origin and k is the electrostatic constant.
It therefore means that from equation (2) we can write the following;

k can cancel out from both side of equation (3), so that we finally obtain the following;

Given;

Substituting these values into equation (4); we obtain the following;


Answer:
Rechargeable batteries can still go flat after repeated use because the materials involved in the reaction lose their ability to charge and regenerate
Explanation:
they go flat because they a rechargeable and sometimes don't always work
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With the switch open, there's no current in the circuit, and therefore
no voltage drop across any of the dissipative elements (the resistor
or the battery's internal impedance). So the entire battery voltage
appears across the switch, and the voltmeter reads 12.0V .
D. physical property
the bonds between molecules of mercury are breaking so it's physical and it's not changing the chemical composition of the substance