<h3><u>Answer;</u></h3>
C. 12 units
<h3><u>Explanation;</u></h3>
- If the strength of the magnetic field at B is 3 units, the strength of the magnetic field at A is 12 units
- Magnetic field strength is one of two ways that the intensity of a magnetic field can be expressed.
- <em><u>The strength of the field is inversely proportional to the square of the distance from the source. This means that If the distance between two points in magnetic filed is doubled the magnetic force between them will fall to a quarter of the initial value. </u></em>
- <em><u>On the other hand, if the distance between two magnets is halved the magnetic force between them will increase to four times the initial value.</u></em>
Answer:

Explanation:
Here we know that for the given system of charge we have no loss of energy as there is no friction force on it
So we will have


now we know when particle will reach the closest distance then due to electrostatic repulsion the speed will become zero.
So we have



so distance moved by the particle is given as



<h3>
Answer:</h3>
Momentum of the given body will be : 75000 Kg m/s
<h3>
Explanation:</h3>
According to Newton's first law of motion, all bodies continue to be in the state of rest or motion unless an external force is applied on the body. We can use this in the case of momentum also
The formula of momentum is given by :

Here, we are given the mass of the body ( m ) as 3000kg and the velocity of the body ( v ) as 25 m/s. On putting the values in the formula:

Momentum is associated with the mass of the moving body and can be defined as the quantity of motion measured as a product of mass and velocity.