Answer:
A permanent magnet 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 moving electric charge creates a magnetic field at all points in the surrounding region.
Explanation:
Magnet field is a region around the magnet in which the magnetic force can be experienced. A magnet has two poles: North pole and South pole. A Magnetic field originates from north pole and ends at south pole.
Magnets are of two types: Permanent magnet and temporary magnet.
A moving charge produces magnetic field. A stationary charge can not produce a magnetic field.
The rate of flowing charge constitutes an electric current. If the cardboard is placed around the current carrying conductor and the iron fillings spread around the cardboard then the iron nails get stick to it. It means that a current carrying conductor creates a magnetic field around it.
Therefore, the true statements from the given statements are as follows;
A permanent magnet 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 moving electric charge creates a magnetic field at all points in the surrounding region.
Friction is the force you get when you (for example) Rub something with another, it's a force that may generate heat and even some resistance. Another example is rubbing your hands together, they get hot, therefore friction is working, without friction you wouldn't be able to stop moving.
In an inelastic collision, only momentum is conserved, while energy is not conserved.
1) Velocity of the nail and the block after the collision
This can be found by using the total momentum after the collisions:

where
m=0.1 kg is the mass of the nail
M=10 kg is the mass of the block of wood
Rearranging the formula, we find

, the velocity of the nail and the block after the collision:

2) The velocity of the nail before the collision can be found by using the conservation of momentum. In fact, the total momentum before the collision is given only by the nail (since the block is at rest), and it must be equal to the total momentum after the collision:

Rearranging the formula, we can find

, the velocity of the nail before the collision:
Kelvin is a base unit of temperature
scale from SI that defines as zero degree Kelvin (absolute zero). The absolute
zero is a hypothetical statement that all molecular movement stops because
there is no transient of energy for the molecules to move. When converting
temperature in degree Celsius to Kelvin, add 273. You are given 600K and you
are asked to find it in degrees Celsius.
T(K) = T(C) + 273
600 K = T(C) + 273
T(C) = 600 – 273
T(C) = 327 °C
<span>The answer is letter B.</span>