Spiral Review Week 1 -Review Quizizz - (2/17-2/21)

Which of the following best describes the nature of electromagnetic waves?

• They require a medium to travel through.

• They can travel through a vacuum.

• They are longitudinal waves.

• They are only visible to the human eye.

Answer explanation

Electromagnetic waves do not require a medium; they can propagate through a vacuum, unlike sound waves. They are transverse waves, not longitudinal, and only a small portion is visible to the human eye.

Consider a scenario where a light wave passes from air into water. What happens to the speed and direction of the wave?

• The speed increases and the wave bends away from the normal.

• The speed decreases and the wave bends towards the normal.

• The speed remains constant and the wave does not bend.

• The speed decreases and the wave bends away from the normal.

Answer explanation

When a light wave enters water from air, its speed decreases due to the higher density of water. Consequently, the wave bends towards the normal, which is the line perpendicular to the surface at the point of entry.

Which of the following is a characteristic of mechanical waves?

• They can travel through a vacuum.

• They require a medium to propagate.

• They are always transverse waves.

• They do not transfer energy.

Answer explanation

Mechanical waves require a medium, such as air or water, to propagate. Unlike electromagnetic waves, which can travel through a vacuum, mechanical waves cannot exist without a material medium.

A student observes a wave on a string and notes that the wave is moving perpendicular to the direction of the string. What type of wave is this?

• Longitudinal wave

• Transverse wave

• Electromagnetic wave

• Surface wave

Answer explanation

The wave moving perpendicular to the direction of the string indicates that it is a transverse wave, where the oscillations occur at right angles to the direction of wave propagation.

In a tug-of-war game, if both teams are pulling with equal force and the rope does not move, what type of forces are acting on the rope?

• Unbalanced forces

• Balanced forces

• Gravitational forces

• Frictional forces

Answer explanation

In this tug-of-war scenario, both teams exert equal force on the rope, resulting in no movement. This indicates that the forces are balanced, as they cancel each other out, keeping the rope stationary.

A book is resting on a table. Which of the following best describes the forces acting on the book?

• The forces are unbalanced, causing the book to move.

• The forces are balanced, keeping the book stationary.

• Only gravitational force is acting on the book.

• Only contact force is acting on the book.

Answer explanation

The book is at rest on the table, indicating that the forces acting on it are balanced. The gravitational force pulling it down is countered by the normal force from the table, keeping the book stationary.

Which of the following is an example of a non-contact force?

• Friction

• Tension

• Gravity

• Normal force

Answer explanation

Gravity is a non-contact force that acts at a distance, pulling objects toward each other without physical contact. In contrast, friction, tension, and normal force require contact between objects.

A magnet attracts a paperclip without touching it. What type of force is this an example of?

• Contact force

• Non-contact force

• Frictional force

• Tension force

Answer explanation

The magnet attracts the paperclip without direct contact, demonstrating a non-contact force. Unlike contact forces, non-contact forces act at a distance, such as magnetic attraction.

• 9.8 N

• 98 N

• 980 N

• 0.98 N

Answer explanation

To find the weight, use the formula: weight = mass × gravity. Here, mass = 10 kg and gravity = 9.8 m/s². Thus, weight = 10 kg × 9.8 m/s² = 98 N. Therefore, the correct answer is 98 N.

How does the mass of an object affect its gravitational force?

• Greater mass results in a weaker gravitational force.

• Greater mass results in a stronger gravitational force.

• Mass does not affect gravitational force.

• Mass only affects gravitational force in a vacuum.

Answer explanation

According to Newton's law of universal gravitation, the gravitational force between two objects increases with greater mass. Therefore, greater mass results in a stronger gravitational force.