Physics

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.

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

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.

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.

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'.

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.

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.

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 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.

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.