Which way does wind blow,
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The gravitational potential energy of the object is 100 J.
Gravitational potential energy stored in an object is the work done in raising the object to a height <em>h</em> against the gravitational force acting on it.
The gravitational force acting on a body is its weight mg, where m is its mass and g, the acceleration due to gravity.
Work done by a force is equal to the product of the force and the displacement made by the point of application of the force.
The weight of the object is given as 20 J and it is raised to a height of 5 m.
The gravitational potential energy of the object is 100 J.
Answer:
A moving electric charge creates a magnetic field at all points in the surrounding region.
An electric current in a conductor creates a magnetic field at all points in the surrounding region.
A permanent magnet creates a magnetic field at all points in the surrounding region.
Explanation:
Magnetic field can be produced by:
- moving charges (i.e. a moving electron, or a current in a conductor)
- A magnet
The strength of the magnetic field produced by a current-carrying wire is
where
I is the current
r is the distance from the wire
As we see from the formula, the magnetic field is produced at all points in the surrounding region, because B becomes zero only when r becomes infinite. The same is true for the magnetic field created by a single moving charge or by a magnet.
The following choices instead are not correct:
- A single stationary electric charge creates a magnetic field at all points in the surrounding region.
- A distribution of electric charges at rest creates a magnetic field at all points in the surrounding region.
Because they involve the presence of stationary charges, and stationary charges do not produce magnetic fields.