Start learning →

B.Tech EEE Magnetism — practice questions — page 3

Explore 72 free Magnetism questions in B.Tech EEE Electrical Engineering. Open each question or exercise to read its content, reference answers and available explanation.

Practise Magnetism with Quill →

Magnetism questions and exercises with answers

Showing questions 61–72 of 72.

A toroidal coil is much like a solenoid bent into a circle. What is the field inside it like?Read the answer and worked solution →Two long parallel wires carry currents I1 and I2 and are separated by a distance r. What is the force per unit length between them?Read the answer and worked solution →Two long parallel wires carry currents in the same direction. What force do they exert on one another?Read the answer and worked solution →Two parallel conductors of infinite length sit 1 m apart in empty space and each carries 1 A. What force per metre does each feel?Read the answer and worked solution →Wires of infinite length cannot be built. How is the definition of the ampere realised in a laboratory?Read the answer and worked solution →How is the electron beam of a cathode ray tube aimed at a chosen point on the screen?Read the answer and worked solution →What is the largest part of an MRI unit, and what field strength does it typically produce?Read the answer and worked solution →Nuclear magnetic resonance was formulated in 1946. Who received the 1952 Nobel Prize in Physics for that work?Read the answer and worked solution →What does functional MRI actually detect when it maps activity in the brain?Read the answer and worked solution →What is a recording of the magnetic field of the beating heart called?Read the answer and worked solution →Which sensor, operating at liquid helium temperature, can measure fields thousands of times smaller than that of the Earth?Read the answer and worked solution →For which task are x ray images more effective than MRI images?Read the answer and worked solution →

Worked practice questions

A toroidal coil is much like a solenoid bent into a circle. What is the field inside it like?

  1. Very strong and straight
  2. Very weak and straight
  3. Very strong and circular
  4. Very weak and circular
Show answer and solution

Correct answer: C. Very strong and circular

1. A toroidal coil is much like a solenoid bent round into a circle. 2. The field inside it is very strong but circular rather than straight. 3. Charged particles then travel in circles following those field lines. 4. Since the particles do not cross field lines, they cannot escape the toroid. 5. This is why the toroidal coil is used to confine reactive particles in a tokamak. _Source: OpenStax College Physics (CC BY 4.0), Ch 22 "Magnetism", section 22.9 Magnetic Fields Produced by Currents: Ampere's Law_

Open this question →

Two long parallel wires carry currents I1 and I2 and are separated by a distance r. What is the force per unit length between them?

  1. F/l = mu0 I1 I2 / (2 pi r)
  2. F/l = mu0 I1 I2 / (2 r)
  3. F/l = 2 pi r / (mu0 I1 I2)
  4. F/l = mu0 I1 I2 r / (2 pi)
Show answer and solution

Correct answer: A. F/l = mu0 I1 I2 / (2 pi r)

1. Wire 1 creates a field at wire 2 of magnitude mu0 I1 / (2 pi r). 2. That field is uniform along wire 2 and perpendicular to it, so the force on wire 2 is I2 l B1. 3. Substituting the field and dividing by the length gives F/l = mu0 I1 I2 / (2 pi r). 4. By the third law of Newton, each wire feels the same size of force. 5. Putting r on top would make wires far apart push harder than wires close together, which is wrong. _Source: OpenStax College Physics (CC BY 4.0), Ch 22 "Magnetism", section 22.10 Magnetic Force between Two Parallel Conductors_

Open this question →

Two long parallel wires carry currents in the same direction. What force do they exert on one another?

  1. They attract each other
  2. They repel each other
  3. They twist each other
  4. They exert no force
Show answer and solution

Correct answer: A. They attract each other

1. Right hand rule 2 gives the field of the first wire at the position of the second. 2. Right hand rule 1 then gives the force on the current in the second wire. 3. Working it through, the force is attractive when the currents run the same way. 4. Currents running in opposite directions repel instead. _Source: OpenStax College Physics (CC BY 4.0), Ch 22 "Magnetism", section 22.10 Magnetic Force between Two Parallel Conductors_

Open this question →

How to practise

  1. Choose a Magnetism question and try to work out your answer.
  2. Open the question to check the correct answer and read its worked solution.
  3. Continue in the app for bite-sized lessons, explanations and review with Quill. You can start without creating an account.

More Electrical Engineering topics

Electric Current, Resistance, and Ohm's LawCircuits and DC Instruments