General Q&A for Class 12 · Page 201
5,215 free answers in General for Class 12 students, across CBSE, ICSE and State boards.
Question & Answer
Questions
- GeneralClass 12All
What are the 7 basic electrical tests?
The seven common electrical tests performed for safety and troubleshooting are: Continuity Test - checks if current can flow through a circuit Voltage Test - measures electrical potential difference Current Test - measures the flow of electric charge Resistance Test - measures opposition to current flow Insulation Resistance Test - checks for insulation b
- GeneralClass 12All
What is AC vs DC electricity?
AC (Alternating Current): Current periodically reverses direction Voltage oscillates in a wave pattern Used for power grids and household supply Easily transformed to different voltages Freuency: 50-60 Hz typically DC (Direct Current): Current flows in one constant direction Voltage remains steady Produced by batteries and solar panels Used in e
- GeneralClass 12All
What are the three types of electricity?
The three main types of electricity are: Static Electricity - stationary electric charges built up on surfaces (like when you shuffle across carpet and get shocked) Direct Current (DC) - electric charge flows steadily in one direction (batteries, solar panels, electronic devices) Alternating Current (AC) - electric charge periodically reverses direction (household power, power grids, large appliances)
- GeneralClass 12All
What is 240 watts in units?
To convert watts to units (kWh), you need to know the operating time. A 240-watt device consumes electricity based on how long it runs: Running for 1 hour = 0.24 units (240W × 1h ÷ 1000 = 0.24 kWh) Running for 4 hours = 0.96 units (approximately 1 unit) Running for 10 hours = 2.4 units The formula is: Units (kWh) = (Watts × Hours) ÷ 1000. So 240 watts itself isn't "in units" until you multiply by ope
- GeneralClass 12All
How many humans will be alive in 2050?
Current UN projections estimate approximately 9.7 billion people will inhabit Earth by 2050, up from about 8 billion in 2024. This projection assumes declining fertility rates in most regions but continued population growth in Africa and parts of Asia. However, predictions vary: some models suggest 8.9 billion to 10.4 billion depending on fertility rates, migration patterns, mortality rates, and unforeseen events (pandemics, climate impacts, technological changes).
- GeneralClass 12All
What will happen on March 16, 2880?
On March 16, 2880, asteroid (29075) 1950 DA has a small chance (0.012% or 1 in 8,300) of impacting Earth. This 1.3 km diameter asteroid is currently the object with the highest known probability of hitting Earth, though those odds are still very low. By 2880, humanity will likely have advanced planetary defense systems to deflect or destroy threatening asteroids. Technologies like gravity tractors, kinetic impactors, or nuclear deflection could easily handle this threat centuries before arriv
- GeneralClass 12All
Will India survive in 2050?
India will not only survive but likely thrive by 2050, projected to become the world's most populous nation (1.6-1.7 billion) and one of the top 3 economies globally. Challenges include water scarcity, climate impacts, infrastructure needs, and air uality, but India's young workforce, technological innovation, democratic institutions, and economic growth position it well. Major cities will expand, technology sectors will grow, and India may lead in renewable energy adoption. Survival isn't th
- GeneralClass 12All
Who is no. 1 in defence?
As of 2025, the United States has the world's most powerful military defense, with a budget exceeding $800 billion annually more than the next 10 countries combined. The U.S. maintains 11 aircraft carrier strike groups, global military bases, advanced technology (F-35s, nuclear submarines, satellite systems), and 1.3 million active personnel. However, military power is multifaceted: China leads in naval ship numbers, Russia in nuclear warheads, and various nations excel in specific capabiliti
- GeneralClass 12All
Who is the 2nd largest army?
By active personnel, India has the second-largest military with approximately 1.45 million active troops, behind only China (2+ million). By total military personnel (including reserves and paramilitary), China is largest, followed by India, then United States. Rankings vary by metric: by firepower index, budget, technological advancement, or nuclear capability, different nations rank differently. India's military is particularly strong in land forces, mountain warfare, and regional power pro
- GeneralClass 12All
Who will have the strongest military in 2050?
Predictions suggest competition between the United States and China for military supremacy by 2050. China is investing heavily in AI, hypersonic weapons, naval expansion, and space militarization, potentially matching or exceeding U.S. capabilities. India may emerge as the third superpower with its growing economy and population. Autonomous systems, cyber warfare, space-based assets, and AI will likely determine dominance more than traditional metrics. However, predicting 25 years ahead is hi
- GeneralClass 12All
Which country is the most powerful in the world 2026?
As of 2026, the United States remains the world's most powerful country overall, considering military strength, economic output ($27+ trillion GDP), technological innovation, cultural influence, diplomatic reach, and reserve currency status (US dollar). However, China challenges U.S. dominance in manufacturing, trade, and regional influence. Power is multidimensional: U.S. leads in military and finance, China in manufacturing and infrastructure, European Union in regulations, and different na
- GeneralClass 12All
Which country will be no. 1 in 2100?
Predicting 75 years ahead is speculative, but several scenarios exist: United States maintains dominance through innovation and institutions. China becomes preeminent if economic growth continues and political system evolves. India emerges supreme with massive population, democracy, and economic growth. African Union or another bloc rises as Africa develops its vast resources and young population. Technological changes (AI, climate, space
- GeneralClass 12All
How many years are left for Earth?
Earth will remain habitable for approximately 1-1.5 billion more years before the Sun's increasing luminosity makes surface conditions too hot for life. The Sun will expand into a red giant in about 5 billion years, likely engulfing Earth. However, human-caused climate change could make Earth uninhabitable for civilization much sooner (centuries) unless we take action. The planet itself will exist until the Sun's death, but habitability is limited by solar evolution and potentially by our own
- GeneralClass 12All
What is the first Earth age?
Earth's age is approximately 4.54 billion years, formed from the solar nebula. Earth's history is divided into eons: 1) Hadean Eon (4.6-4.0 billion years ago, earliest age, molten surface), 2) Archean Eon (4.0-2.5 billion years ago, first life emerged), 3) Proterozoic Eon (2.5 billion-541 million years ago, oxygen atmosphere developed), and 4) Phanerozoic Eon (541 million years ago-present, complex life flourished). The "first Earth age" would be the Hadean Eon, characterized by intense heat
- GeneralClass 12All
Will humans live until 2050?
Yes, humanity will almost certainly exist in 2050, only 25 years away. While we face challenges like climate change, potential pandemics, nuclear risks, and AI safety concerns, these threats are unlikely to cause human extinction within such a short timeframe. Civilization might experience disruptions, but human adaptability, technological solutions, and global cooperation make survival highly probable. Individual longevity also supports this: most people alive today could reasonably expect t
- GeneralClass 12All
What is gravity?
Gravity is a fundamental force of nature that attracts objects with mass toward one another. It's the invisible force that keeps your feet on the ground, holds the Moon in orbit around Earth, and binds galaxies together. Every object with mass exerts a gravitational pull on every other object, though we typically only notice gravity's effects when at least one object is extremely massive, like a planet or star. Sir Isaac Newton first described gravity mathematically in the 17th century, and A
- GeneralClass 12All
What is the formula for gravity?
The universal law of gravitation formula is: F = G(m₁m₂)/r² Where: F = gravitational force between two objects G = gravitational constant (6.674 × 10⁻¹¹ N⋅m²/kg²) m₁ and m₂ = masses of the two objects r = distance between the centers of the two objects For calculating weight on Earth's surface, we use the simpler formula: F = mg, where m is mass and g is t
- GeneralClass 12All
What is 9.8 called?
9.8 m/s² is called the acceleration due to gravity or simply "gravitational acceleration" on Earth's surface. The value represents how uickly objects accelerate when falling (ignoring air resistance). Each second, a falling object's velocity increases by 9.8 meters per second. This value is used worldwide in physics calculations and is fundamental to understanding weight, falling objects, projectile motion, and orbital mechanics.
- GeneralClass 12All
What is the unit of gravity?
Gravity (as acceleration) is measured in m/s² (meters per second suared) in the SI system, or feet per second suared (ft/s²) in imperial units. Gravitational force is measured in Newtons (N) in SI or pounds-force (lbf) in imperial. The gravitational constant G has units of N·m²/kg² or m³/(kg·s²). The choice of unit depends on whether you're discussing acceleration, force, or the gravitational constant.
- GeneralClass 12All
What is the full name of gravity?
Gravity's formal scientific name is "gravitational force" or "gravitation". The phenomenon was systematically described by Isaac Newton as the "universal law of gravitation," which states that all masses attract each other. The term "gravity" comes from the Latin word "gravitas," meaning weight or heaviness. In Einstein's general relativity, gravity is understood not as a force but as the curvature of spacetime caused by mass and energy.