Tag: science & technology

The wave equation v = f × λ (velocity = frequency × wavelength) shows that if velocity stays constant and frequency increases, wavelength must decrease. They are inversely proportional. In a given medium, wave speed is fixed by the medium's properties.

Frequency is defined as the number of complete wave cycles (or crests) that pass a fixed point per unit time. By counting how many crests pass in a given time interval and dividing by that time, you directly calculate frequency. Wavelength (A) is the distance between crests, amplitude (B) is wave height, and velocity (C) is speed - none of these are calculated by counting crests over time.

Momentum equals mass times velocity (p = mv), so SI units are kg × m/s = kg m/s. A Newton-second (N s) is equivalent: 1 N = 1 kg m/s², so 1 N s = 1 kg m/s. Option A (N/s) is incorrect, B (kg m/s²) is acceleration units, and C (Pa s) is viscosity units.

Weight is the gravitational force acting on an object, calculated as W = mg (mass × gravitational acceleration). Mass (C) is intrinsic matter content, momentum (A) is mass × velocity, and density (B) is mass per volume. Weight is specifically the force due to gravity.

Speed is a scalar quantity (magnitude only) while velocity is a vector quantity (magnitude + direction). This is the fundamental difference - both measure rate of motion but velocity includes directional information. Option A correctly identifies this distinction despite the typo.

Electromagnetic waves (including light) are unique because they can travel through a vacuum without any medium. All other waves listed (sound, water, compressional) are mechanical waves that require a material medium to propagate. Light waves self-propagate via oscillating electric and magnetic fields.

Tim Berners-Lee invented the World Wide Web in 1989 while working at CERN. He developed the first web browser, web server, and the fundamental protocols (HTTP, HTML) that power the web today. Seymour Cray was a supercomputer pioneer, Engelbart invented the mouse and hypertext systems, and Zuse was an early computer engineer.

Sabeer Bhatia co-founded Hotmail along with Jack Smith in 1996. Hotmail was one of the first web-based email services and was later acquired by Microsoft. Bill Gates, Paul Allen, and Steve Ballmer were all Microsoft figures but not Hotmail's inventors. Hotmail's name was derived from HTML (HoTMaiL).