10.2 Fields at Work

Question 1

Marks: 1

When a mass is moved against the force of gravity, work is done such that the change in work done, ΔW is equal to the change in gravitational potential ΔV.

Which line correctly identifies the equation and named variables for work done when moving a mass in a gravitational field?

	symbol equation	word equation
A.	Fs	force × distance
B.	FΔV	force × change in gravitational potential
C.	ms	mass × distance
D.	mΔV	mass × change in gravitational potential

Key Concepts

Potential & Potential Energy

Question 2

Marks: 1

When a mass moves through a gravitational field the magnitude of the potential energy E_P changes. Which equation could be used to correctly calculate this?

$∆ E_{p} = G M m (\frac{1}{r_{1}} - \frac{1}{r_{2}})$
$∆ E_{p} = G M m (- \frac{1}{r_{1}} - \frac{1}{r_{2}})$
$∆ E_{p} = G M m (\frac{1}{r_{1}} + \frac{1}{r_{2}})$
$∆ E_{p} = G M m (\frac{1}{r_{1}} \times \frac{1}{r_{2}})$

Key Concepts

Potential & Potential Energy

Question 3

Marks: 1

Two point charges q₁ and 2q₂are separated by distance 2r.

What is the value of the gravitational potential energy E_p?

$E_{p} = \frac{2 q_{1} q_{2}}{4 π ε_{0} r}$
$E_{p} = \frac{q_{1} q_{2}}{8 π ε_{0} r}$
$E_{p} = \frac{q_{1} q_{2}}{4 π ε_{0} r}$
$E_{p} = \frac{2 q_{1} q_{2}}{8 π ε_{0} r}$

Key Concepts

Potential Energy Calculations

Question 4

Marks: 1

An electric field can be defined in terms of the variation of electric potential at different points in the field.

Which graph correctly represents this relationship?

10-2-ib-hl-mcqs-easy-q4

Key Concepts

Potential Gradient

Question 5

Marks: 1

Which quantity does the following statement define?

The work done by moving a positive test charge from one point to another in an electric field.

Potential gradient
Electric field strength
Gravitational potential
Potential difference

Key Concepts

Potential Difference

Question 6

Marks: 1

Two parallel metal plates are separated by distance, d and have a potential difference of V_e.

Which equation correctly gives the magnitude of the electric force acting on a stationary charged particle between the plates if the particle has a charge of Q?

$F = \frac{E}{Q}$
$F = k \frac{q_{1} q_{2}}{d^{2}}$
$F = m a$
$F = \frac{Q V_{e}}{d}$

Key Concepts

Potential Gradient & Difference

Question 7

Marks: 1

Read the following statements about the escape velocity on Earth. Which ones are correct?

Escape velocity;

Increases as the mass of the object increases
Depends on the mass of the Earth and is not affected by the mass of the object
Is defined as the minimum speed that allows an object to escape a gravitational field with no further energy input

I. only
I. and II.
II. and III.
III. only

Key Concepts

Escape Velocity

Question 8

Marks: 1

The equation for linear orbital speed is

$v = \sqrt{\frac{G M}{r}}$

Which statement is a consequence of this equation?

Orbital speed is the same for all objects, regardless of their mass, when their orbital radius is the same.
Orbital speed is the same for all objects, regardless of their mass, when they orbit the same planet.
The gravitational constant, G, can be derived if orbital speed and radius are both known.
Time period, T can be derived from orbital speed and radius.

Key Concepts

Orbital Motion, Speed & Energy

Question 9

Marks: 1

Gravitational and electrostatic forces are similar in many ways. Which statements are correct about both?

Both electrostatic forces and gravitational forces are always attractive
Both electrostatic forces and gravitational forces may be attractive or repulsive
Both electrostatic forces and gravitational forces follow an inverse square law
The equations used to calculate these forces rely on knowing certain universal constants

I and III only
III and IV only
I, II, and III only
II, III, and IV only

Key Concepts

Forces & Inverse-Square Law Behaviour

Question 10

Marks: 1

A charged particle in an electric field will experience a force on it that will cause it to move. The three particles X, Y and Z are experiencing a force which deflects their motion as shown. What three particles could X, Y and Z be?

10-2-ib-hl-mcqs-easy-q10

	X	Y	Z
A.	beta-minus particle	photon	nucleus
B.	alpha particle	neutron	photon
C.	neutron	electron	alpha-particle
D.	electron	beta-plus particle	neutron

Key Concepts

Forces on Charges & Masses

DP IB Physics: HL

Topic Questions

10.2 Fields at Work

Question 1

Key Concepts

Question 2

Key Concepts

Question 3

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Question 4

Key Concepts

Question 5

Key Concepts

Question 6

Key Concepts

Question 7

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Question 8

Key Concepts

Question 9

Key Concepts

Question 10

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