Answer:
Right hand thumb rule : It is a rule used to find the magnetic field direction around current carrying wire .
Explanation:
It states that : "If you grasp conductor in your right hand such that thumb points in upward direction ,then the direction in which our finger curls gives the direction of magnetic field or magnetic lines of forces" .
This rule proves that :Current can give rise to magnetism .
Around every current carrying conductor there exist a magnetic field which can be easily felt .
According to this rule : When a current flows in upward direction ,the finger curls in anticlockwise direction and when direction of current reverses ,then the direction of field also reverses .
Answer:
Relation between initial speed of bullet and height h is given as

Explanation:
As we know that system of block and bullet swings up to height h after collision
So we have

so we have

so speed of the block + bullet just after the impact is given by above equation
Now we also know that there is no force on the system of bullet + block in the direction of motion
So we can use momentum conservation

now we have

Answer:
A fundamental theory that provides a description of the physical properties of nature at the scale of atoms and subatomic particles.
Explanation:
Electrons are a stable sub atomic particle that has a negative charge and is found in all atoms and is the main carrier of electricity through solids.
In a metal, some of the electrons can escape from the atoms and are free to move around inside the metal. These electrons are referred to as 'conduction electrons'.
<span>A current is a flow of charge. In metal a current is the flow of the conduction electrons through the metal. This can occur when connected to battery for example: The battery pumps the conduction electrons around the circuit. </span>