The only statement that makes sense as to which one describes an effect of changes in Earth's magnetic field is the first one - <span>Southern lights are seen at high altitude places like Alaska.
Normally, Southern lights are seen around the South Pole, which means that it is quite odd for them to be seen in Alaska, which is near the North Pole.</span>
Answer:
The coastal zone is not a stable and constant environment, but a dynamic place that can change rapidly in response to natural processes such as seasonal weather patterns. Waves, winds, currents, tides and storms are the major forces on the coast.
Explanation:
intensity of a star is inversely depends on the square of the distance from the star
we can say it is given as
here we know that
also we know that
now we will have
so other star is at distance 60 Light years
Answer:
The gravitational force is related to the mass of each object.
The gravitational force is an attractive force.
Explanation:
Gravitational force is a long range force of attraction between any two masses.
Mathematically given as :
where:
are the masses
r= distance between the center of mass of the two objects.
G= gravitational constant = 
From the above relation of eq. (1) it is clear that,
Gravitational force is inversely proportional to the square of the distance and directly proportional to the masses.
The mass of an object is independent of its size due to the fact that density may vary for different objects.
The force of gravity varies with height as:
where:
gravity at height 
of the center of mass of the object from the center of mass of the earth.
and we know that force:
where: m= mass of the object.
Answer:
2.64 x 10⁻⁶T
Explanation:
The magnitude of the magnetic field produced by a long straight wire carrying current is given by Biot-Savart law as follows: "The magnetic field strength is directly proportional to the current on the wire and inversely proportional to the distance from the wire". This can be written mathematically as;
B = (μ₀ I) / (2π r) ----------------(i)
B is magnetic field
I is current through the wire
r is the distance from the wire
μ₀ is the magnetic constant = 4π x 10⁻⁷Hm⁻¹
From the question;
I = 0.7A
r = 0.053m
Substitute these values into equation (i) as follows;
B = (4π x 10⁻⁷ x 0.7) / (2π x 0.053)
B = 2.64 x 10⁻⁶T
Therefore the approximate magnitude of the magnetic field at that location is 2.64 x 10⁻⁶T
