Quantum Theory is commonly related to Quantum Mechanics, or the physics of sub-atomic particles. Quantum Theory defines the theories or educated ideas behind Quantum Mechanics. I believe this is the answer you are looking for.
2nd and only 2nd option is right
Answer:
C. 
Explanation:
Let initial charges on both spheres be,

When the sphere C is touched by A, the final charges on both will be,
#Now, when C is touched by B, the final charges on both of them will be:

Now the force between A and B is calculated as:

Hence the electrostatic force becomes 3F/8
A. through a relatively short distance.
The speed is actually called the drift speed of the electron.
Answer:
Velocity is 2.17 m/s at an angle of 9.03° above X-axis.
Explanation:
Mass of object 1 , m₁ = 300 g = 0.3 kg
Mass of object 2 , m₂ = 400 g = 0.4 kg
Initial velocity of object 1 , v₁ = 5.00i-3.20j m/s
Initial velocity of object 2 , v₂ = 3.00j m/s
Mass of composite = 0.7 kg
We need to find final velocity of composite.
Here momentum is conserved.
Initial momentum = Final momentum
Initial momentum = 0.3 x (5.00i-3.20j) + 0.4 x 3.00j = 1.5 i + 0.24 j kgm/s
Final momentum = 0.7 x v = 0.7v kgm/s
Comparing
1.5 i + 0.24 j = 0.7v
v = 2.14 i + 0.34 j
Magnitude of velocity

Direction,

Velocity is 2.17 m/s at an angle of 9.03° above X-axis.