The subatomic particles that acts like a mini-magnet is electron. Electrons are negatively charged sub atomic particles in an atom. The electron spin is a property of an electron that makes it behave like it's spinning; a spinning electron produces a magnetic field that makes it behave like a tiny magnet in an atom.
Answer:

Upward
Explanation:
We are given that
Mass of scarp paper,
1mg=
Distance,d =8 mm=
Magnitude of electric force =
Where 
Substitute the values


Gravitational force act in downward direction.
The electric force acts in opposite direction and magnitude of electric force is equal to gravitational force.
Hence, the direction of electric force is upward.
Answer:
A. A resistor alters current and a switch turns current on and off
Explanation:
Resistor is the passive component that reduces the flow of current. Switch is the electrical device that turns on or off the current by closing and opening the electrical circuit.
Thus option A. A resistor alters current and a switch turns current on and off is correct.
Efficiency
Explanation:
Efficiency is a ratio/percentage that is useful in comparing the energy transferred by a device to the total energy supplied to it.
Percentage efficiency =
x 100
- As with most system, none is 100% efficient.
- During energy is transferred some are lost and only a little portion is used in doing actual work by the machine.
- This validates the third law of thermodynamics which proposes that no system is 100% efficient.
- A 100% efficiency implies total energy input is used doing all the work.
- This is impossible. The bulk of the energy goes into heating the system.
learn more:
Third law of thermodynamics brainly.com/question/3564634
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