Tag: science & technology

At higher altitudes (hills), atmospheric pressure is lower than at sea level. Lower pressure reduces the boiling point of water - typically about 1°C drop for every 285 meters of elevation. This is why water boils below 100°C on mountains.

The ozone hole was discovered in 1985 by British scientists from the British Antarctic Survey who were monitoring ozone levels over Antarctica. The Antarctic region experiences unique atmospheric conditions due to the polar vortex and extremely cold temperatures, which lead to ozone depletion during spring months.

Clickjacking is a malicious technique where attackers trick users into clicking on something different from what they perceive by overlaying invisible or disguised elements on a webpage. While option A mentions revealing confidential information, clickjacking is more broadly about deceiving users into performing unintended actions like deleting content, changing settings, or making unwanted purchases. The description in A captures the deceptive essence but is slightly narrow in focus.

Artificial satellites primarily use solar cells (photovoltaic cells) that convert sunlight directly into electrical energy. This is the most practical and reliable power source for satellites as they operate in space where sunlight is continuously available. Nuclear reactors are used only in specific large-scale missions, dynamos require mechanical rotation, and thermopiles produce insufficient power for satellite operations.

Albert Einstein received the Nobel Prize in Physics in 1921 specifically for his discovery of the photoelectric effect, not for relativity as commonly believed. His work explained how light can eject electrons from materials and established the quantum nature of light, which was revolutionary in understanding light-matter interactions.

Hans Christian Oersted discovered in 1820 that an electric current flowing through a wire produces a magnetic field around it, causing a nearby compass needle to deflect. This was the first demonstration of the relationship between electricity and magnetism. Faraday later expanded on this with electromagnetic induction, while Volta worked on batteries and Henry on self-induction.

To answer this question, the user needs to know what humidity is and how it is measured. Humidity refers to the amount of moisture or water vapor in the air. It is measured using an instrument called a hygrometer.

Option A, Barometer, is not the correct answer because a barometer is used to measure atmospheric pressure, not humidity.

Option B, Thermometer, is not the correct answer because a thermometer is used to measure temperature, not humidity.

Option C, Hygrometer, is the correct answer because a hygrometer is specifically designed to measure humidity. It works by measuring the amount of moisture in the air and expressing it as a percentage of the maximum amount of moisture that the air can hold at a given temperature.

Option D, Hydrometer, is not the correct answer because a hydrometer is used to measure the density of a liquid or the specific gravity of a substance, not humidity.

Therefore, the answer is: C. Hygrometer.

Edwin Hubble provided the first observational evidence for the Big Bang theory in 1929 by discovering that galaxies are moving away from each other and that more distant galaxies recede faster (Hubble's Law). This expansion of the universe suggested it began from a single point. While others developed theoretical aspects, Hubble's astronomical observations were the foundational evidence.

-40° is the temperature where Fahrenheit and Celsius scales intersect. This can be derived from F = (9/5)C + 32. Setting F = C gives -40° as the solution. At 0°, F = 32°. At 40°C, F = 104°, and at 100°C, F = 212°, so none of these are equal.

The period of a simple pendulum depends only on its length (T = 2π√(L/g)) and is independent of mass. Changing the pendulum bob's mass doesn't affect the period, so the clock continues to keep correct time. The pendulum's timekeeping is based on length and gravity, not mass.