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Topic D - Fields - IB Questionbank | RevisionDojo

Practice Topic D - Fields with authentic IB Physics exam questions for both SL and HL students. This question bank mirrors Paper 1A, 1B, 2 structure, covering key topics like mechanics, thermodynamics, and waves. Get instant solutions, detailed explanations, and build exam confidence with questions in the style of IB examiners.

Paper

Level

Question 1

HLPaper 2

The diagram shows two point masses: mass $A = 2m$ and mass $B = m$ . Point $X$ lies between them, at a distance $2d$ from mass $A$ and $\sqrt{2} d$ from mass B.

State the condition for the net gravitational field at point $X$ to be zero.

[1]

Show that the magnitudes of the gravitational fields due to each mass at point $X$ are equal.

[2]

If $m = 5.0 \times 10^{24} \ \text{kg}$ and $d = 1.0 \times 10^8 \ \text{m}$ , calculate the magnitude of the gravitational field at $X$ due to mass $A$ .

[2]

If a test mass were placed at point $X$ , describe qualitatively what would happen if it were slightly displaced toward mass A.

[2]

Question 2

SLPaper 2

The Moon orbits the Earth at an average distance of $3.84 \times 10^8\ \text{m}$ . The mass of the Earth is $5.97 \times 10^{24}\ \text{kg}$ and $G = 6.67 \times 10^{-11}\ \text{N m}^2 \text{kg}^{-2}$ .

State the direction of the gravitational field produced by the Earth.

[1]

Calculate the gravitational field strength at the Moon’s orbit due to the Earth.

[2]

Explain why the Moon remains in orbit despite this weak field.

[1]

Question 3

HLPaper 2

A coil of wire with $N = 150$ turns is placed in a region where the magnetic flux through the coil changes uniformly from $2.0 \times 10^{-4}\ \text{Wb}$ to $0$ in $0.10\ \text{s}$ .

State Faraday’s law of electromagnetic induction.

[1]

Calculate the magnitude of the average induced emf in the coil.

[2]

Explain how Lenz’s law determines the direction of the induced emf.

[1]

Question 4

HLPaper 2

Two point charges, $q_1 = +6.0\ \mu\text{C}$ and $q_2 = -2.0\ \mu\text{C}$ , are separated by a distance of $0.50\ \text{m}$ .

Calculate the electric potential at a point P located $0.40\ \text{m}$ from $q_1$ and $0.30\ \text{m}$ from $q_2$ .

[2]

Determine the work done to bring a $+1.0\ \mu\text{C}$ charge from infinity to point P.

[2]

Calculate the electric field strength at point P due to each charge and determine the net electric field vector relation at point P.

[2]

Find the magnitude of the net electric field at point P.

[1]

Explain why the direction of the electric field is not the same as the direction of the electric potential gradient in this case.

[2]

Question 5

HLPaper 2

A rectangular coil with 120 turns, length $0.10\ \text{m}$ and width $0.05\ \text{m}$ is pulled at constant velocity $2.0\ \text{m s}^{-1}$ into a uniform magnetic field of $0.40\ \text{T}$ perpendicular to the plane of the coil. It takes $0.025\ \text{s}$ for the entire coil to enter the field.

Calculate the change in magnetic flux linkage through the coil during this interval.

[2]

Determine the average emf induced during this time.

[2]

Explain how the induced emf would change if the normal to the coil makes an angle $\theta$ (where $0 < \theta < 90^\circ$ ) with the magnetic field lines.

[2]

Question 6

HLPaper 2

A straight conductor of length $0.50\ \text{m}$ moves at a speed of $6.0\ \text{m s}^{-1}$ perpendicular to a magnetic field of strength $0.40\ \text{T}$ .

State the condition under which a moving conductor in a magnetic field induces an emf.

[1]

Calculate the induced emf across the ends of the conductor.

[2]

Explain what would happen to the induced emf if the conductor moved parallel to the magnetic field.

[1]

Question 7

SLPaper 2

An electron is accelerated from rest through a potential difference of $500\ \text{V}$ and enters a region of uniform magnetic field of strength $0.030\ \text{T}$ directed perpendicular to its velocity. Charge of electron $q = 1.60 \times 10^{-19}\ \text{C}$ , mass $m = 9.11 \times 10^{-31}\ \text{kg}$ .

Calculate the speed of the electron just before it enters the magnetic field.

[2]

Determine the radius of its circular path in the magnetic field.

[2]

Calculate the frequency of revolution of the electron.

[2]

Calculate the number of revolutions the electron completes in $1.0 \times 10^{-6}\ \text{s}$ .

[1]

Describe qualitatively what would happen to the electron’s trajectory if the magnetic field strength were gradually increased.

[1]

Question 8

SLPaper 2

A spacecraft of mass $1200\ \text{kg}$ is in orbit at an altitude of $500\ \text{km}$ above the surface of Earth. Earth's radius is $6.37 \times 10^6\ \text{m}$ , and its mass is $5.97 \times 10^{24}\ \text{kg}$ . $G = 6.67 \times 10^{-11}\ \text{N m}^2 \text{kg}^{-2}$ .

Calculate the orbital speed of the spacecraft.

[2]

Determine the total mechanical energy of the spacecraft in orbit.

[2]

Calculate the difference in gravitational potential energy between the spacecraft at orbit and on the surface of the Earth.

[2]

If the spacecraft is to escape Earth’s gravity from orbit, calculate the additional speed required (i.e., the difference between escape speed and orbital speed).

[2]

Explain why escape speed is independent of the mass of the escaping object.

[1]

Question 9

SLPaper 2

A satellite is in circular orbit $2.00 \times 10^6\ \text{m}$ above the surface of Earth. The radius of Earth is $6.37 \times 10^6\ \text{m}$ , and Earth’s mass is $5.97 \times 10^{24}\ \text{kg}$ .

Calculate the distance from the centre of the Earth to the satellite.

[1]

Determine the gravitational field strength at the satellite’s altitude.

[2]

Calculate the orbital speed required for the satellite to stay in circular orbit.

[2]

Explain why the gravitational field strength decreases with altitude.

[1]

Question 10

HLPaper 2

A bar of length $0.60\ \text{m}$ is placed on conducting rails connected to a resistor. The bar moves to the right at $3.0\ \text{m s}^{-1}$ through a uniform magnetic field of $0.50\ \text{T}$ directed into the page. The total resistance of the circuit is $2.0\ \Omega$ .

Calculate the emf induced across the bar.

[2]

Determine the current in the circuit.

[1]

Calculate the power dissipated in the resistor.

[1]

Explain the energy transformation taking place in this system.

[2]

Paper

Level

Question 1

HLPaper 2

The diagram shows two point masses: mass $A = 2m$ and mass $B = m$ . Point $X$ lies between them, at a distance $2d$ from mass $A$ and $\sqrt{2} d$ from mass B.

State the condition for the net gravitational field at point $X$ to be zero.

[1]

Show that the magnitudes of the gravitational fields due to each mass at point $X$ are equal.

[2]

If $m = 5.0 \times 10^{24} \ \text{kg}$ and $d = 1.0 \times 10^8 \ \text{m}$ , calculate the magnitude of the gravitational field at $X$ due to mass $A$ .

[2]

If a test mass were placed at point $X$ , describe qualitatively what would happen if it were slightly displaced toward mass A.

[2]

Question 2

SLPaper 2

State the direction of the gravitational field produced by the Earth.

[1]

Calculate the gravitational field strength at the Moon’s orbit due to the Earth.

[2]

Explain why the Moon remains in orbit despite this weak field.

[1]

Question 3

HLPaper 2

A coil of wire with $N = 150$ turns is placed in a region where the magnetic flux through the coil changes uniformly from $2.0 \times 10^{-4}\ \text{Wb}$ to $0$ in $0.10\ \text{s}$ .

State Faraday’s law of electromagnetic induction.

[1]

Calculate the magnitude of the average induced emf in the coil.

[2]

Explain how Lenz’s law determines the direction of the induced emf.

[1]

Question 4

HLPaper 2

Two point charges, $q_1 = +6.0\ \mu\text{C}$ and $q_2 = -2.0\ \mu\text{C}$ , are separated by a distance of $0.50\ \text{m}$ .

Calculate the electric potential at a point P located $0.40\ \text{m}$ from $q_1$ and $0.30\ \text{m}$ from $q_2$ .

[2]

Determine the work done to bring a $+1.0\ \mu\text{C}$ charge from infinity to point P.

[2]

Calculate the electric field strength at point P due to each charge and determine the net electric field vector relation at point P.

[2]

Find the magnitude of the net electric field at point P.

[1]

Explain why the direction of the electric field is not the same as the direction of the electric potential gradient in this case.

[2]

Question 5

HLPaper 2

Calculate the change in magnetic flux linkage through the coil during this interval.

[2]

Determine the average emf induced during this time.

[2]

Explain how the induced emf would change if the normal to the coil makes an angle $\theta$ (where $0 < \theta < 90^\circ$ ) with the magnetic field lines.

[2]

Question 6

HLPaper 2

A straight conductor of length $0.50\ \text{m}$ moves at a speed of $6.0\ \text{m s}^{-1}$ perpendicular to a magnetic field of strength $0.40\ \text{T}$ .

State the condition under which a moving conductor in a magnetic field induces an emf.

[1]

Calculate the induced emf across the ends of the conductor.

[2]

Explain what would happen to the induced emf if the conductor moved parallel to the magnetic field.

[1]

Question 7

SLPaper 2

Calculate the speed of the electron just before it enters the magnetic field.

[2]

Determine the radius of its circular path in the magnetic field.

[2]

Calculate the frequency of revolution of the electron.

[2]

Calculate the number of revolutions the electron completes in $1.0 \times 10^{-6}\ \text{s}$ .

[1]

Describe qualitatively what would happen to the electron’s trajectory if the magnetic field strength were gradually increased.

[1]

Question 8

SLPaper 2

Calculate the orbital speed of the spacecraft.

[2]

Determine the total mechanical energy of the spacecraft in orbit.

[2]

Calculate the difference in gravitational potential energy between the spacecraft at orbit and on the surface of the Earth.

[2]

If the spacecraft is to escape Earth’s gravity from orbit, calculate the additional speed required (i.e., the difference between escape speed and orbital speed).

[2]

Explain why escape speed is independent of the mass of the escaping object.

[1]

Question 9

SLPaper 2

Calculate the distance from the centre of the Earth to the satellite.

[1]

Determine the gravitational field strength at the satellite’s altitude.

[2]

Calculate the orbital speed required for the satellite to stay in circular orbit.

[2]

Explain why the gravitational field strength decreases with altitude.

[1]

Question 10

HLPaper 2

Calculate the emf induced across the bar.

[2]

Determine the current in the circuit.

[1]

Calculate the power dissipated in the resistor.

[1]

Explain the energy transformation taking place in this system.

[2]

Paper

Level

Question 1

HLPaper 2

The diagram shows two point masses: mass $A = 2m$ and mass $B = m$ . Point $X$ lies between them, at a distance $2d$ from mass $A$ and $\sqrt{2} d$ from mass B.

State the condition for the net gravitational field at point $X$ to be zero.

[1]

Show that the magnitudes of the gravitational fields due to each mass at point $X$ are equal.

[2]

If $m = 5.0 \times 10^{24} \ \text{kg}$ and $d = 1.0 \times 10^8 \ \text{m}$ , calculate the magnitude of the gravitational field at $X$ due to mass $A$ .

[2]

If a test mass were placed at point $X$ , describe qualitatively what would happen if it were slightly displaced toward mass A.

[2]

Question 2

SLPaper 2

State the direction of the gravitational field produced by the Earth.

[1]

Calculate the gravitational field strength at the Moon’s orbit due to the Earth.

[2]

Explain why the Moon remains in orbit despite this weak field.

[1]

Question 3

HLPaper 2

A coil of wire with $N = 150$ turns is placed in a region where the magnetic flux through the coil changes uniformly from $2.0 \times 10^{-4}\ \text{Wb}$ to $0$ in $0.10\ \text{s}$ .

State Faraday’s law of electromagnetic induction.

[1]

Calculate the magnitude of the average induced emf in the coil.

[2]

Explain how Lenz’s law determines the direction of the induced emf.

[1]

Question 4

HLPaper 2

Two point charges, $q_1 = +6.0\ \mu\text{C}$ and $q_2 = -2.0\ \mu\text{C}$ , are separated by a distance of $0.50\ \text{m}$ .

Calculate the electric potential at a point P located $0.40\ \text{m}$ from $q_1$ and $0.30\ \text{m}$ from $q_2$ .

[2]

Determine the work done to bring a $+1.0\ \mu\text{C}$ charge from infinity to point P.

[2]

Calculate the electric field strength at point P due to each charge and determine the net electric field vector relation at point P.

[2]

Find the magnitude of the net electric field at point P.

[1]

Explain why the direction of the electric field is not the same as the direction of the electric potential gradient in this case.

[2]

Question 5

HLPaper 2

Calculate the change in magnetic flux linkage through the coil during this interval.

[2]

Determine the average emf induced during this time.

[2]

Explain how the induced emf would change if the normal to the coil makes an angle $\theta$ (where $0 < \theta < 90^\circ$ ) with the magnetic field lines.

[2]

Question 6

HLPaper 2

A straight conductor of length $0.50\ \text{m}$ moves at a speed of $6.0\ \text{m s}^{-1}$ perpendicular to a magnetic field of strength $0.40\ \text{T}$ .

State the condition under which a moving conductor in a magnetic field induces an emf.

[1]

Calculate the induced emf across the ends of the conductor.

[2]

Explain what would happen to the induced emf if the conductor moved parallel to the magnetic field.

[1]

Question 7

SLPaper 2

Calculate the speed of the electron just before it enters the magnetic field.

[2]

Determine the radius of its circular path in the magnetic field.

[2]

Calculate the frequency of revolution of the electron.

[2]

Calculate the number of revolutions the electron completes in $1.0 \times 10^{-6}\ \text{s}$ .

[1]

Describe qualitatively what would happen to the electron’s trajectory if the magnetic field strength were gradually increased.

[1]

Question 8

SLPaper 2

Calculate the orbital speed of the spacecraft.

[2]

Determine the total mechanical energy of the spacecraft in orbit.

[2]

Calculate the difference in gravitational potential energy between the spacecraft at orbit and on the surface of the Earth.

[2]

If the spacecraft is to escape Earth’s gravity from orbit, calculate the additional speed required (i.e., the difference between escape speed and orbital speed).

[2]

Explain why escape speed is independent of the mass of the escaping object.

[1]

Question 9

SLPaper 2

Calculate the distance from the centre of the Earth to the satellite.

[1]

Determine the gravitational field strength at the satellite’s altitude.

[2]

Calculate the orbital speed required for the satellite to stay in circular orbit.

[2]

Explain why the gravitational field strength decreases with altitude.

[1]

Question 10

HLPaper 2

Calculate the emf induced across the bar.

[2]

Determine the current in the circuit.

[1]

Calculate the power dissipated in the resistor.

[1]

Explain the energy transformation taking place in this system.

[2]

Topic D - Fields Questionbank