12 PHYSICS QLD EA MC 2021

Leptons do not experience the

• weak force

• strong force

• gravitational

• electromagnetic

Calculate the initial horizontal velocity of a projectile with an initial velocity of 38 m s^–1 at an angle of 42° up from the horizontal.

• 25 m s^–1

• 28 m s^–1

• 34 m s^–1

• 40 m s^–1

Identify the correct formula for the mass–energy equivalence relationship.

• E=mc²

• E=mgh

The diagram shows two charges (q1 and q2) separated by a distance (d).

There is a force, F, acting between the two charges.

Calculate the magnitude of the force acting between the two charges if d is halved and the charge of q2 is doubled.

• 1F

• 2F

• 4F

• 8F

Mesons are

• subatomic particles composed of one quark and one antiquark.

• elementary particles that are classified as leptons.

• elementary particles exchanged between quarks.

• subatomic particles composed of three quarks.

Electromagnetic radiation is

• extremely high-frequency radiation emitted from the nucleus of some radionuclides.

• the emission of energy as waves or particles, especially high-energy particles, that causes ionisation.

• a wave of energy produced by an oscillating electric charge, resulting in mutually perpendicular electric and magnetic fields.

• radiant energy consisting of synchronised oscillations of electric and magnetic fields, or electromagnetic waves, propagated at the speed of light in a vacuum.

Normal force is the force acting along an imaginary line

• parallel to the surface.

• perpendicular to the surface.

• opposite to the gravitational force.

• in the same direction as the gravitational force.

The diagram shows two displacement vectors.

Calculate the resultant vector above the horizontal axis when Vector A is added to Vector B.

• 43.6 m at 36.6°

• 43.6 m at 53.4°

• 48.4 m at 18.1°

• 48.4 m at 71.9°

The Bohr atomic model describes an atom as

• the smallest particle of any substance.

• a small dense nucleus orbited by electrons.

• electrons scattered throughout a sphere of positively charged fluid.

• a small positive nucleus surrounded by negative electrons in set orbits of fixed energy.

Proper length is the length measured in the frame of reference where the object is

• at rest.

• in motion.

• accelerating.

• in motion but not accelerating.