Cuestionario: Fundamentals of Physics and Earth Systems — 20 preguntas

1. A sound wave has a shorter wavelength than another sound wave. What is the most likely effect on its pitch?

A. It will be quieter

B. It will have a higher pitch

C. It will travel faster

D. It will have a lower pitch

Answer: (B)

Explicación

For sound waves, shorter wavelength corresponds to higher pitch. Pitch is related to the frequency and wavelength of the wave, not to loudness or speed here.

2. What does wavelength measure in a wave?

A. The distance between repeating points along the wave

B. The number of waves produced each second

C. The speed at which the wave travels

D. The maximum height of the wave above equilibrium

Answer: (A)

Explicación

Wavelength is the distance between repeating points on a wave, measured along the direction of travel. The maximum height is amplitude, and the number per second is frequency.

3. What property of a light wave is linked to its brightness?

A. Frequency

B. Wavelength

C. Amplitude

D. Refraction angle

Answer: (C)

Explicación

Light brightness is associated with amplitude, so a bigger amplitude means brighter light. Wavelength is more directly linked to color and refraction behavior.

4. Why does a prism split white light into different colors?

A. Bright light reflects more strongly inside the prism

B. The prism creates new colors from nothing

C. Different colors have different masses

D. Different wavelengths refract by different amounts

Answer: (D)

Explicación

A prism separates white light because different wavelengths refract by different amounts. This changes the direction of each color differently as it passes through the material.

5. Which type of electromagnetic radiation has the longest wavelengths?

A. Microwaves

B. Radio waves

C. Visible light

D. X-rays

Answer: (B)

Explicación

Radio waves have the longest wavelengths in the electromagnetic spectrum. The spectrum is ordered by wavelength and frequency.

6. What is true of electromagnetic radiation as it travels?

A. It only travels in solids

B. It requires particles to carry the energy

C. It can travel through space without a medium

D. It must move through air or water

Answer: (C)

Explicación

Electromagnetic radiation can travel through space and does not require particles traveling through a medium. This is why it can carry energy and information through a vacuum.

7. A pole vaulter reaches a higher top speed. What happens to the vaulter’s kinetic energy?

A. It stays the same because only mass matters

B. It increases because kinetic energy depends on speed

C. It becomes gravitational potential energy immediately

D. It decreases because speed reduces energy storage

Answer: (B)

Explicación

Kinetic energy increases with both mass and the square of speed, so a higher top speed raises kinetic energy. The formula is Ek = 1/2 mv^2.

8. In a hydroelectric system, what is the main energy transfer from the falling water?

A. Gravitational potential energy to electrical energy through turbine motion

B. Chemical energy to sound energy through turbines

C. Light energy to gravitational energy through pipes

D. Electrical energy to thermal energy through friction

Answer: (A)

Explicación

Water’s gravitational potential energy is used to spin turbines, and that motion is then converted into electrical energy. This is the key transfer in hydroelectric power generation.

9. Which investigation is a testable question about magnetism?

A. Why are magnets interesting to people?

B. How does magnet count affect the number of nails picked up?

C. Do magnets feel heavy when held?

D. Which magnet is the most famous?

Answer: (B)

Explicación

A testable question changes a measurable factor and observes a measurable outcome, such as magnet count and nails picked up. The other choices are not measurable investigations.

10. Which non-contact force best explains pulling a non-magnetic aluminium car with a rubbed PVC pipe and wool?

A. Gravitational force

B. Frictional force

C. Magnetic force

D. Electrostatic force

Answer: (D)

Explicación

The force involved is electrostatic force, which comes from attraction or repulsion due to electric charge. Rubbing the PVC pipe increases charge buildup, strengthening the pull.

11. What does resistance measure in an electric circuit?

A. How strongly a component opposes current flow

B. How much voltage a battery can provide

C. How much charge is stored by a component

D. How quickly a component converts energy to light

Answer: (A)

Explicación

Resistance describes how strongly a component opposes current flow. It is not the same as voltage, charge storage, or light output.

12. A 12 V battery is connected in series to a 5 ohm resistor and a 1 ohm bulb. What is the current in the circuit?

A. 6 A

B. 2 A

C. 12 A

D. 4 A

Answer: (B)

Explicación

Using Ohm’s law, the total resistance is 6 ohms, so current equals 12 ÷ 6 = 2 A. This matches the series-circuit calculation given.

13. Why is a magnet needed in an electric motor?

A. It turns electrical energy directly into heat

B. It stores electrical energy until the motor starts

C. It increases the resistance of the circuit

D. Its magnetic field interacts with the coil’s magnetic field and makes the coil spin

Answer: (D)

Explicación

The motor works because the magnet’s field interacts with the coil’s field, producing rotation. The magnet is not mainly acting as an energy store or heater.

14. Which investigation would be a suitable testable question about electromagnet strength?

A. How does the room temperature affect the length of the wire?

B. How does iron-nail width affect the number of staples picked up?

C. How does the shape of the power switch affect the number of staples picked up?

D. How does the color of the coil affect the number of staples picked up?

Answer: (B)

Explicación

This question changes one measurable factor and observes a measurable result, which makes it testable. The other options do not focus on a relevant factor for electromagnet strength.

15. What is the correct sequence of the water cycle?

A. Runoff, precipitation, condensation, evaporation

B. Condensation, evaporation, runoff, precipitation

C. Precipitation, runoff, evaporation, condensation

D. Evaporation, condensation, precipitation, runoff

Answer: (D)

Explicación

The correct order is evaporation, condensation, precipitation, then runoff. This is the continuous movement of water through the system.

16. Which Earth system does a flowing lava example belong to?

A. Atmosphere

B. Hydrosphere

C. Biosphere

D. Geosphere

Answer: (D)

Explicación

Flowing lava is part of the solid Earth, so it belongs to the geosphere. By contrast, a lifeless polluted river would belong to the hydrosphere.

17. What is the main result of photosynthesis?

A. Glucose and oxygen are made from carbon dioxide and water using light energy

B. Oxygen is removed from the atmosphere and turned into nitrogen

C. Carbon dioxide and water are made from glucose and oxygen using light energy

D. Glucose is broken down into carbon dioxide and water to release energy

Answer: (A)

Explicación

Photosynthesis uses light energy to form glucose and oxygen from carbon dioxide and water. The other options describe respiration or unrelated processes.

18. Why does respiration get described as the opposite of photosynthesis for certain gases?

A. It uses carbon dioxide and produces oxygen

B. It uses oxygen and produces carbon dioxide

C. It stores energy only in sunlight

D. It turns water directly into glucose

Answer: (B)

Explicación

Respiration requires oxygen and releases carbon dioxide, which is the reverse of photosynthesis for those gases. It also releases energy from glucose.

19. What advantage is stated for the new 3D artificial eye?

A. It may offer sharper vision than a human eye in the future

B. It eliminates the need for any medical research

C. It works only with external spectacles and cables

D. It replaces the need for a retina with a flat image sensor

Answer: (A)

Explicación

A stated advantage is the possibility of sharper vision than a human eye in the future. The other options describe limitations of older devices or incorrect claims.

20. What is a nanowire?

A. A thick wire used to carry household current

B. A tiny wire with a diameter around 10^-9 m

C. An artificial lens that uses external cables

D. A chemical process that creates oxygen in the eye

Answer: (B)

Explicación

A nanowire is defined as a very small wire with a diameter around 10^-9 m. It is not a lens, a current-carrying household wire, or a chemical process.