1.
What is the unit of force in the International System of Units?
Correct Answer
A. Newton
Explanation
In the International System of Units (SI), the unit of force is the Newton. This unit is named after Sir Isaac Newton in recognition of his work on classical mechanics, particularly his second law of motion. One Newton is defined as the force required to accelerate one kilogram of mass at a rate of one meter per second squared. This unit is fundamental across all physics-related disciplines, helping to quantify the amount of force applied in various scenarios, from simple everyday movements to complex scientific experiments.
2.
What does the law of conservation of energy state?
Correct Answer
C. Energy can be neither created nor destroyed
Explanation
The law of conservation of energy is a fundamental concept in physics stating that the total amount of energy in an isolated system remains constant over time. This means that energy can change forms, such as kinetic energy to potential energy and vice versa, but it cannot be created out of nothing or completely destroyed. This principle is crucial in all areas of physics and engineering because it enables the calculation and prediction of energy flow and transformation in all physical processes, thereby ensuring that energy budgets in any given scenario are balanced.
3.
What property of a wave is measured in Hertz?
Correct Answer
C. Frequency
Explanation
Frequency, measured in Hertz (Hz), is a critical property of waves that describes how often the wave cycles occur per second. High-frequency waves have more cycles per second compared to low-frequency waves. This property is applicable across various types of waves, including sound, light, and electromagnetic waves, helping scientists and engineers determine how waves behave in different mediums and under different conditions. Frequency plays a key role in defining both the physical and perceptual properties of waves, such as the pitch of sound and the color of light.
4.
What force keeps planets in orbit around the sun?
Correct Answer
B. Gravitational force
Explanation
Gravitational force is the force of attraction that exists between any two masses, which is what keeps the planets in their orbits around the sun. This fundamental force of nature was first described by Isaac Newton in his law of universal gravitation. In the context of planetary motion, the gravitational force exerted by the sun pulls the planets toward it, while the planets' inertia causes them to move in a forward direction, resulting in elliptical orbits. This delicate balance between gravitational pull and inertia is what sustains the stable orbits of planets in the solar system.
5.
What is the phenomenon of light bending around an object called?
Correct Answer
C. Diffraction
Explanation
Diffraction is a fundamental wave phenomenon that occurs when waves, such as light, sound, or water waves, encounter obstacles or openings in their path that are comparable in size to their wavelength. When this occurs, waves bend around or spread out from the edges of the obstacle, creating patterns that can be observed and measured. In the case of light, diffraction is responsible for various optical effects and is key in phenomena such as the spreading of light beams passing through small apertures and the interference patterns observed in many optical experiments.
6.
What type of energy is possessed by a moving object?
Correct Answer
B. Kinetic energy
Explanation
Kinetic energy is the energy that an object possesses due to its motion. It is calculated based on the object's mass and the square of its velocity, following the formula KE = 1/2 mv². This type of energy is observable in everyday phenomena such as moving vehicles, flowing rivers, and flying projectiles. Understanding kinetic energy is crucial in fields ranging from mechanical engineering to aerospace, as it helps predict how objects will move and interact under various forces, ensuring the effective and safe design of systems.
7.
What device is used to measure electric current?
Correct Answer
B. Ammeter
Explanation
An ammeter is a measuring instrument used to measure the electric current in a circuit. It is typically connected in series to a circuit so it can measure the flow of charge through the wire without substantially altering the circuit. Accurate measurement of electric current is vital in many areas of electronics and electrical engineering, allowing professionals to monitor, diagnose, and regulate power flow in circuits to ensure efficient and safe operation of electrical systems and devices.
8.
What is the change in velocity per unit time called?
Correct Answer
A. Acceleration
Explanation
Acceleration is defined as the rate at which an object changes its velocity. It is a vector quantity, which means it has both a magnitude and a direction. In physics, understanding acceleration is essential for describing the motion of objects under various forces. It plays a critical role in everything from vehicle safety design to space travel, and is also a fundamental concept in Newton's laws of motion, which describe how and why objects move.
9.
In a vacuum, which color of light travels the fastest?
Correct Answer
D. All colors travel at the same speed
Explanation
The speed of light in a vacuum is a fundamental constant, approximately 299,792,458 meters per second. All electromagnetic waves, including visible light of different colors, travel at this same speed in a vacuum. The color of light is determined by its wavelength and frequency, but these do not affect its speed in a vacuum.
10.
What is the SI unit of power?
Correct Answer
A. Watt
Explanation
The Watt, named after James Watt, the inventor of the steam engine, is the International System of Units (SI) measure of power. It quantifies the rate of energy transfer and is defined as one Joule per second. The unit is used universally in all applications involving the measurement of power, from electrical appliances to engines. Understanding how to measure and calculate power using watts enables engineers and scientists to design systems that efficiently use energy, from small household devices to large industrial machines.