Answer: physical or mechanical weathering
Explanation:
Mechanical weathering which is also referred to as the physical weathering occurs when a rock is broken down into smaller pieces. In this case, there will be a physical change of the rock but its composition will not change.
Some examples include ice freezing and expansion of the cracks in the rock, Smstrong winds that carrycpieces of sand which then sandblast surfaces, moving water which causes abrasion etc.
The correct answer is
<span>A. decreasing the current
In fact, the magnetic field produced by a current carrying wire is given by
</span>

<span>where
</span>

is the vacuum permeability
<span>I is the current in the wire
r is the distance from the wire at which the field is calculated
We see from the formula that the intensity of the field, B, is directly proportional to the current I, so if the current decreases, the magnetic field strength B decreases as well.</span>
Answer:
The magnifying power of this telescope is (-60).
Explanation:
Given that,
The focal length of the objective lens of an astronomical telescope, 
The focal length of the eyepiece lens of an astronomical telescope, 
To find,
The magnifying power of this telescope.
Solution,
The ratio of focal length of the objective lens to the focal length of the eyepiece lens is called magnifying of the lens. It is given by :


m = -60
So, the magnifying power of this telescope is 60. Therefore, this is the required solution.