Physics

Isaac Newton is renowned for formulating the three laws of motion and the law of universal gravitation, which are fundamental principles in classical physics.

Light is guided through the core of an optical fiber due to total internal reflection, which occurs when light traveling within the core hits the core-cladding boundary at an angle greater than the critical angle, causing it to reflect back into the core.

Space waves are electromagnetic waves that travel directly from the transmitting antenna to the receiving antenna and are used for line of sight (LOS) communication, such as in TV and FM radio transmission.

LED stands for Light Emitting Diode, which is a semiconductor device that emits light when an electric current passes through it. The other options do not accurately represent the acronym LED.

DC stands for 'direct current,' which is a type of electrical current that flows in one direction only.

IC stands for 'Integrated Circuit,' which is a set of electronic circuits on a small chip of semiconductor material. This is the most common and widely accepted meaning in electronics.

MSI stands for 'Medium Scale Integrated Circuits,' which refers to integrated circuits containing hundreds of logic gates. This is a standard term in digital electronics.

Ole Rømer was the first scientist to successfully measure the speed of light in 1676 by observing the timing variations of eclipses of Jupiter's moon Io, demonstrating that light has a finite speed.

Ultrasonic waves are sound waves with frequencies higher than the upper audible limit of human hearing, which is about 20 kilohertz (20,000 hertz). Therefore, ultrasonic waves have frequencies more than 20 kilohertz.

Gravitational waves were first directly detected by LIGO in 2015, with the discovery announced in 2016. In 2017, LIGO and Virgo collaborations announced further detections of gravitational waves, confirming their existence and opening a new era in astronomy. The other options are incorrect or nonsensical in this context.