D. It must be able to be magnetized
Explanation:
The requirement for a core to be used in an electromagnet is that it must be able to be magnetized.
An electromagnet is a type of magnet produced by electricity.
- They typically run and produce magnetic fields in the vicinity of electrical currents.
- These magnets are not permanent magnets.
- When the electrical current is removed, the magnetic property of the substance is lost.
- The core of an electromagnet is usually made up of a material that can easily be magnetized in the presence of magnetic fields.
- Some of the materials used are cobalt, iron, nickel.
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Electromagnet brainly.com/question/2191993
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The concave mirror is a spherical-shaped mirror that has an inner curved surface. Hence, option (4) is correct.
What is a concave mirror?
The concave mirrors are spherical-shaped mirrors that are painted on the outward surface. It is also known as the converging mirror, having the recessed inner reflecting surface.
- The concave mirrors are generally used for the purpose to focus the light. For that, they might have a reflecting surface, curved inwards, and the reflection of light is limited to the single focal point.
- The reflecting surface of the concave mirror has its vertex or midpoint lying farther away from the objects than the edges.
Thus, we can conclude that the surface of the concave mirror is curved inward. Hence, option (4) is correct.
Learn more about the concave mirror here:
brainly.com/question/13300307
I believe the answer is the fourth one, hope this helps
Answer:
7.75 s
Explanation:
Newton's second law:
∑F = ma
35 N = (70 kg) a
a = 0.5 m/s²
Given v₀ = 0 m/s and Δx = 15 m:
Δx = v₀ t + ½ at²
(15 m) = (0 m/s) t + ½ (0.5 m/s²) t²
t = 7.75 s
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