The equation Q=CV (Charge = product of Capacitance and potential difference) tells us that the maximum charge that can be stored on a capacitor is equal to the product of it's capacitance and the potential difference across it. In this case the potential difference across the capacitor will be 12.0V (assuming circuit resistance is negligable) and it has a capacitance of 18.0μf or 18.0x10^-6f, therefore charge equals (18.0x10^-6)x12=2.16x10^-4C (Coulombs).
Answer:
C). 
Explanation:
As we know that capacitance of a given capacitor is

now we know that energy stored in the capacitor plates

here if all the dimensions of the capacitor plate is doubled
then in that case

here area becomes 4 times on doubling the radius and the distance between the plates also doubles
So new capacitance is now

so capacitance is doubled
now the final energy stored between the plates of capacitor is given as

so the final energy is


Answer:
Earth pulls the sun towards itself with a force equal to the ratio of the mass of the sun to the mass of Earth
Maintaining an orbit has nothing to do with the satellite's speed.
ANY (tangential) speed is enough to stay in orbit, if the satellite
just stays away from Earth's atmosphere.
If the satellite completely stops moving 'sideways' at all, and just
hangs there, then the forces of gravity between the satellite and
the Earth will pull them together ... the satellite will fall into the
atmosphere and then to the ground.