DP Physics Questionbank

Description

Nature of science:

Paradigm shift: The move from direct, observable actions being responsible for influence on an object to acceptance of a field’s “action at a distance” required a paradigm shift in the world of science. (2.3)

Understandings:

• Gravitational fields
• Electrostatic fields
• Electric potential and gravitational potential
• Field lines
• Equipotential surfaces

Applications and skills:

• Representing sources of mass and charge, lines of electric and gravitational force, and field patterns using an appropriate symbolism
• Mapping fields using potential
• Describing the connection between equipotential surfaces and field lines

Guidance:

• Electrostatic fields are restricted to the radial fields around point or spherical charges, the field between two point charges and the uniform fields between charged parallel plates
• Gravitational fields are restricted to the radial fields around point or spherical masses and the (assumed) uniform field close to the surface of massive celestial bodies and planetary bodies
• Students should recognize that no work is done in moving charge or mass on an equipotential surface

Data booklet reference:

Theory of knowledge:

• Although gravitational and electrostatic forces decrease with the square of distance and will only become zero at infinite separation, from a practical standpoint they become negligible at much smaller distances. How do scientists decide when an effect is so small that it can be ignored?

Utilization:

• Knowledge of vector analysis is useful for this sub-topic (see Physics sub-topic 1.3)

Aims:

• Aim 9: models developed for electric and gravitational fields using lines of forces allow predictions to be made but have limitations in terms of the finite width of a line

Directly related questions

• 16N.1.HL.TZ0.31: Two parallel metal plates are connected to a dc power supply. An electric field forms in the...
• 17M.1.HL.TZ1.29: An electric field acts in the space between two charged parallel plates. One plate is at zero...
• 17M.1.HL.TZ1.31: Two point charges are at rest as shown. At which position is the electric field strength...
• 17M.1.HL.TZ2.30: A positive charge Q is deposited on the surface of a small sphere. The dotted lines...
• 17M.2.HL.TZ1.6a: Outline how this diagram shows that the gravitational field strength of planet X decreases with...
• 20N.1.HL.TZ0.31: P and S are two points on a gravitational equipotential surface around a planet. Q and R are two...
• 17N.1.HL.TZ0.33: An isolated hollow metal sphere of radius R carries a positive charge. Which graph shows...
• 17N.1.HL.TZ0.31: A charge of −3 C is moved from A to B and then back to A. The electric potential at A is +10 V...
• 21M.2.HL.TZ1.2c.i:

  Show that the gravitational potential due to the planet and the star at the surface of the planet is about −5 × 10⁹J kg⁻¹.

• 21M.1.HL.TZ1.30: A particle with charge −2.5 × 10−6 C moves from point X to point Y due to a uniform electrostatic...
• 21M.1.HL.TZ2.31:

  The points X and Y are in a uniform electric field of strength $E$. The distance OX is $x$ and the distance OY is $y$.

    

  What is the magnitude of the change in electric potential between X and Y?

  A.  $Ex$

  B.  $Ey$

  C.  $E(x + y)$

  D.  $E\sqrt{x^2 + y^2}$

• 21M.1.HL.TZ2.30:

  An object of mass $m$ released from rest near the surface of a planet has an initial acceleration $z$. What is the gravitational field strength near the surface of the planet?

  A.  $z$

  B.  $\frac{z}{m}$

  C.  $mz$

  D.  $\frac{m}{z}$

• 18M.1.HL.TZ1.30:

  Four identical, positive, point charges of magnitude Q are placed at the vertices of a square of side 2d. What is the electric potential produced at the centre of the square by the four charges?

                                                               

  A.     0

  B.     $\frac{4kQ}{d}$

  C.     $\frac{\sqrt{2}kQ}{d}$

  D.     $\frac{2\sqrt{2}kQ}{d}$

• 18M.1.HL.TZ1.31: The diagram shows 5 gravitational equipotential lines. The gravitational potential on each line...
• 18M.2.HL.TZ1.8c.i:

  On the diagram, draw and label the equipotential lines at –0.4 V and –0.8 V.

• 18M.2.HL.TZ2.6d:

  The mass of the asteroid is 6.2 × 10¹² kg. Calculate the gravitational force experienced by the planet when the asteroid is at point P.

• 18M.2.HL.TZ2.6b:

  A planet has a radius of 3.1 × 10⁶ m. At a point P a distance 2.4 × 10⁷ m above the surface of the planet the gravitational field strength is 2.2 N kg^–1. Calculate the gravitational potential at point P, include an appropriate unit for your answer.

• 18M.1.HL.TZ2.30: A positive point charge is placed above a metal plate at zero electric potential. Which...
• 18M.1.HL.TZ2.28: A moon of mass M orbits a planet of mass 100M. The radius of the planet is R and the...
• 18M.1.HL.TZ2.29: The diagram shows the electric field and the electric equipotential surfaces between two...
• 18M.2.HL.TZ2.6a.ii:

  Show that V = –g(R + h).

• 18M.2.HL.TZ2.6a.iii:

  Draw a graph, on the axes, to show the variation of the gravitational potential V of the planet with height h above the surface of the planet.

  

• 21N.1.HL.TZ0.30: The diagram shows equipotential lines for an electric field. Which arrow represents...
• 22M.1.HL.TZ1.32:

  A charged sphere in a gravitational field is initially stationary between two parallel metal plates. There is a potential difference V between the plates.

  

  Three changes can be made:

  I.   Increase the separation of the metal plates
  II.  Increase V
  III. Apply a magnetic field into the plane of the paper

  What changes made separately will cause the charged sphere to accelerate?

  A.  I and II only

  B.  I and III only

  C.  II and III only

  D.  I, II and III

• 22M.2.HL.TZ2.7a: Outline what is meant by electric potential at a point.
• 22M.2.HL.TZ2.7c.i: Comment on the angle at which the object meets equipotential surfaces around the sphere.
• 19M.2.HL.TZ2.9b:

  The diagram shows some of the electric field lines for two fixed, charged particles X and Y.

  

  The magnitude of the charge on X is $Q$ and that on Y is $q$. The distance between X and Y is 0.600 m. The distance between P and Y is 0.820 m.

  At P the electric field is zero. Determine, to one significant figure, the ratio $\frac{Q}{q}$.

• 19M.2.HL.TZ1.8a.ii: The plastic film begins to conduct when the electric field strength in it exceeds 1.5 MN C–1....
• 19M.1.HL.TZ2.30: An electron is fixed in position in a uniform electric field. What is the position for which the...
• 19M.1.HL.TZ1.32: A negative charge Q is to be moved within an electric field E, to equidistant points from its...