Exin Exam CDCP Topic 4 Question 25 Discussion

Actual exam question for Exin's CDCP exam

Question #: 25
Topic #: 4

By what are magnetic fields of the type 'H' or 'B' created?

AMagnetic fields are created when an electric current flows; the greater the current, the stronger the magnetic field.

BMagnetic fields are created by the magnetic flux of the earth which varies per month.

CMagnetic fields are created by voltage; the greater the voltage, the stronger the magnetic field.

DMagnetic fields are created when there is a high level of common mode noise (CMN); the greater the common mode noise (CMN), the stronger the magnetic field.

Show Suggested Answer

Suggested Answer: A

According to the CDCP Preparation Guide1, magnetic fields of the type 'H' or 'B' are created when an electric current flows through a conductor, such as a wire or a coil. The magnetic field strength 'H' is proportional to the current 'I' and the number of turns 'N' of the coil, and inversely proportional to the length 'l' of the coil. The magnetic flux density 'B' is proportional to the magnetic field strength 'H' and the permeability '' of the medium in which the magnetic field exists. The greater the current, the stronger the magnetic field and the magnetic flux density. The relationship between 'H', 'B', 'I', 'N', 'l', and '' can be expressed by the following equations:

H = N I / l

B = H

1: CDCP Preparation Guide, page 23, section 2.4.2.1 2: Difference between B and H in magnetic fields?3, page 1, section 1 4: Magnetic field | Definition & Facts5, page 1, section 1

by Karma at Sep 18, 2024, 09:28 AM

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My

2 months ago

I agree with Jesusita, the relationship between electric current and magnetic fields is well-established in science.

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Art

2 months ago

Haha, voltage creating magnetic fields? That's a good one! Obviously, it's the current that does the trick. Option A is the way to go.

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Jesusita

3 months ago

I think option A makes sense because I remember learning about electromagnetism in physics class.

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Graciela

3 months ago

I was stuck between A and D, but I think A makes the most sense. Common mode noise doesn't create magnetic fields, it's all about that electric current flow.

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Olive

2 months ago

Common mode noise doesn't create magnetic fields, so A is the correct answer.

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Ryan

2 months ago

Yeah, the greater the current, the stronger the magnetic field.

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Shanice

2 months ago

I agree, magnetic fields are definitely created by electric current flow.

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3 months ago

A) Magnetic fields are created when an electric current flows; the greater the current, the stronger the magnetic field.

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