Answer:
1) The strength of the electromagnet increases → Place a magnetic core inside the coil of wire
2) The electromagnet turns off → Turn off the battery supply
3) The poles of the electromagnet reverse → Change the direction in which the current flows
Explanation:
when current passes through a coil it behaves a an electromagnet.
Magnetic field strength is given by
B = μ N I
N is no of turns and
I is the current through coil
μ is permeability of the medium or core in the coil.
1). Magnetic core increase permeability μ so it will strengthen magnetic field:
B = <u>μ</u> N I
2). When the battery turns off current becomes zeroi.e I=0
So B = μ N * 0
⇒ B = 0
so electromagnet turns off
3). Direction of magnetic field can be determine by right hand rule, i.e curl the fingers in the direction of current, thumb will point in the direction of north pole.
so changing current direction will change direction of magnetic field.
Answer:
The inverse of f equals the inverse of d Subscript o Baseline plus the inverse of d Subscript I Baseline.
Explanation:
The lens equation shows the relation among focal length of the lens, image distance and object distance. It can be expressed as:
= 
+ 
where: f is the focal length of the lens, 
is the object distance to the lens and 
is the image distance to the lens.
The lens equation can be used to determine the unknown value among the variables f , and .
The correct answer for the statement “All the scientific
theories used to explain the formation of the solar system are non-testable”. The
answers outdated, imaginative and unacceptable are wrong. These theories are
not proven and yet are not tested due to the complexity.
Answer: Physical changes in nature could then be erosion in a mountain, the melting of snow, and a river freezing over from the cold. Since none of these changes affect the chemical composition of the mountain, the snow, or the river, they are physical changes.
Explanation:
Answer: Real image
Explanation:
converging lens will only produce a real image if the object is located beyond the focal point (i.e., more than one focal length away).
