Physics

The theory of the Expanding Universe was first proposed based on observations by Edwin Hubble, who discovered that galaxies are moving away from us, indicating expansion. Einstein and Newton did not propose this theory, and 'Gahleo' appears to be a misspelling or incorrect name.

Ernest Rutherford discovered the nucleus of the atom through his gold foil experiment, which showed that atoms have a small, dense, positively charged center called the nucleus.

A Geiger-Muller counter is a device used to detect ionizing radiation, including alpha particles, beta particles, and gamma rays (photons). It does not directly detect protons or neutrons. Since the options list only protons, neutrons, photons, and 'None of the above', and the Geiger-Muller counter detects ionizing particles including photons but also other particles, the best answer among the given options is 'None of the above' because it detects more than just photons. The original answer 'C' (Photons) is partially correct but incomplete, as the counter detects various ionizing radiations, not only photons.

The concept "All motion is relative" was first clearly proposed by Galileo Galilei, who laid the foundation for classical mechanics and relativity of motion. Albert Einstein later developed the theory of relativity, but the original idea is attributed to Galileo.

Isaac Newton formulated the three laws of motion and the law of universal gravitation, which are fundamental principles in classical physics. This distinguishes him from the other scientists listed, who contributed to different areas of science.

Space waves travel in a straight line and are used for line of sight (LOS) communication, making them suitable for applications like microwave and satellite communication. Cable waves and antenna waves are not standard terms used to describe LOS communication waves.

Neon gas is most commonly used in neon signs because it emits a distinct bright reddish-orange glow when an electric current passes through it, making it ideal for colorful lighting displays.

The volume of the copper sphere is converted into the volume of the wire. Using volume formulas, the length of the wire is calculated as approximately 2430 m, which corresponds to option C.

Since the volume of the wire remains constant, and volume = cross-sectional area × length, decreasing the radius to one-third reduces the area by (1/3)^2 = 1/9. To keep volume constant, length must increase by a factor of 9.

The volume of water needed to raise the tank level by 2 meters is calculated as: 200 m × 150 m × 2 m = 60,000 m³. The cross-sectional area of the pipe is 1.5 m × 1.25 m = 1.875 m². The flow velocity is given as 20 km/h, which converts to 20,000 m / 3600 s ≈ 5.56 m/s. The volumetric flow rate is area × velocity = 1.875 m² × 5.56 m/s ≈ 10.42 m³/s. The time to fill the tank is volume / flow rate = 60,000 m³ / 10.42 m³/s ≈ 5755 seconds, which is approximately 95.9 minutes. This rounds to 96 minutes, matching option D. Therefore, the correct answer is D, not B as originally stated.

The volume of water displaced by the boat sinking 1 cm is equal to the volume of the submerged part of the boat: 3 m × 2 m × 0.01 m = 0.06 m³. Using the density of water (1000 kg/m³), the mass of the man is 0.06 × 1000 = 60 kg.

Convection is a mode of heat transfer that requires a medium like water, whereas space is a vacuum where heat transfer occurs primarily through radiation. Thus, the analogy matches 'Water : Convection' with 'Space : Radiation'.

A Joule is a unit of energy, and a Pascal is a unit of pressure. Therefore, the analogy is correct: Joule relates to Energy as Pascal relates to Pressure.

A kilometre is a unit of distance, and similarly, a poundal is a unit of force. Thus, the analogy compares units to their respective physical quantities.

Ohm, Watt, Volt, and Ampere are all units related to electricity and electrical measurements, making 'Ampere' the most similar word among the options.

The 2017 Nobel Prize in Physics was awarded for the observation of gravitational waves, specifically recognizing the first direct detection of these waves by the LIGO collaboration. The correct phrasing is 'Observation of Gravitational Waves,' with 'Far' being unnecessary and 'First' less precise in this context.

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.

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.

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.

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.

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.

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

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.

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.

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.