Topic 6: Fields and Forces

Question 1

Newton’s Law of Universal Gravitation

Answer 1

The gravitational force between any two point objects is always attractive; proportional to the product of their masses and inversely proportional to the square of their separation.

Question 2

Gravitational Field Strength

Answer 2

The force per unit mass on a small test mass placed in the field

Question 3

Universal gravitational constant

Answer 3

The constant of proportionality in the Universal Law of Gravitation. G = 6.7 x 10–11 Nm2kg–2

Question 4

Law of conservation of charge

Answer 4

Electric charge cannot be created nor destroyed.

Question 5

Coulomb’s Law

Answer 5

The electric force between two point charges is proportional to the product of the point charges and inversely proportional to the square of their distance apart.

Question 6

Electric field strength

Answer 6

The force per unit charge on a small positive test charge placed in the field.

Question 7

Electric field patterns

Answer 7

A pattern of lines of force which show the direction in which a small positive test charge would feel a force.

Question 8

Force on a current carrying conductor

Answer 8

A charge moving in a magnetic field or a current flowing in a conductor in a magnetic field feel a force calculated according to the given equations. It’s direction is predicted by Fleming’s Left Hand Rule.

Question 9

Magnetic field strength

Answer 9

The force per unit length per unit current on a current-carrying conductor at right angles to the field lines. Unit is tesla (T).

Question 10

Gravitational force

Answer 10

Force due to gravity, between two masses

Question 11

Gravitational field

Answer 11

Area in which an object experiences a force due to gravity