GK: Class 12 General Q&A · Page 84
3,658 free answers on GK (General) for Class 12 students, across CBSE, ICSE and State boards.
Question & Answer
Questions
- GeneralClass 12All
How to calculate unit mass?
Unit mass typically means mass per single unit or item: Unit mass = Total mass ÷ Number of units For example, if 10 apples have a total mass of 2 kg, the unit mass per apple is 2 kg ÷ 10 = 0.2 kg (200g). This concept helps in pricing, packaging, and manufacturing.
- GeneralClass 12All
What is an example of Ohm's Law?
A practical example: Your smartphone charger outputs 5 volts, and your phone's charging circuit has 2.5 ohms of resistance. Using I = V ÷ R, the charging current is 5V ÷ 2.5Ω = 2 amperes. This explains why your phone charges at a specific rate based on the charger's voltage and the device's internal resistance.
- GeneralClass 12All
What is resistance in Ohm's Law?
Resistance is the opposition to current flow in a circuit, measured in ohms (Ω). In Ohm's Law, resistance is calculated as R = V ÷ I. Different materials have different resistance levels—copper has low resistance (good conductor), while rubber has high resistance (good insulator). Resistance converts electrical energy into heat.
- GeneralClass 12All
Why is Ohm's Law used?
Ohm's Law is used to design, analyze, and troubleshoot electrical circuits. It helps engineers calculate the correct resistor values, determine power requirements, size wires appropriately, and diagnose circuit problems. Whether you're building a simple LED circuit or complex electronic equipment, Ohm's Law provides the mathematical foundation for safe and effective circuit design.
- GeneralClass 12All
How many types of Ohm's Law are there?
There is fundamentally one Ohm's Law, but it can be expressed in three different forms (V = I × R, I = V ÷ R, and R = V ÷ I) depending on which variable you're solving for. Some people also refer to the "power triangle" formulas that combine Ohm's Law with power calculations, but the core principle remains the same.
- GeneralClass 12All
What is the voltage formula?
The voltage formula from Ohm's Law is V = I × R. This means voltage equals current multiplied by resistance. For example, if 2 amperes flows through a 5-ohm resistor, the voltage across it is 2A × 5Ω = 10 volts.
- GeneralClass 12All
What is the original formula for Ohm's Law?
The original formula for Ohm's Law is V = I × R, where voltage (V) equals current (I) multiplied by resistance (R). This is the form Georg Ohm first described in 1827, establishing that voltage is the product of current and resistance in a circuit.
- GeneralClass 12All
What is Ohm's Law in a simple circuit?
In a simple circuit, Ohm's Law explains how the three basic electrical properties interact. For instance, if you connect a battery (voltage source) to a light bulb (resistance), the amount of current flowing depends on both the battery's voltage and the bulb's resistance. A 9-volt battery with a 3-ohm bulb produces 3 amperes of current (9V ÷ 3Ω = 3A).
- GeneralClass 12All
What is an ohm unit?
An ohm (symbol: Ω) is the SI unit of electrical resistance. One ohm is defined as the resistance that allows one ampere of current to flow when one volt of electrical potential is applied. Named after Georg Ohm, it measures how much a material opposes the flow of electric current.
- GeneralClass 12All
What is current and voltage?
Current is the flow of electrical charge through a conductor, measured in amperes (A). Think of it as the amount of water flowing through a pipe. Voltage is the electrical potential difference that pushes current through a circuit, measured in volts (V). It's like the water pressure that makes water flow. Together, they determine how electrical energy moves through a circuit.
- GeneralClass 12All
How do you calculate Ohm's Law?
To calculate using Ohm's Law, identify which two values you know and which one you need to find. For example, if you have a 12-volt battery connected to a 4-ohm resistor and need to find the current, use I = V ÷ R, which gives you 12V ÷ 4Ω = 3A. Always ensure your units are correct: volts for voltage, amperes for current, and ohms for resistance.
- GeneralClass 12All
What is the mass?
Mass is a fundamental property of matter that measures: The amount of matter in an object An object's resistance to acceleration (inertia) How strongly gravity pulls on an object Mass is measured in kilograms, remains constant regardless of location, and is different from weight, which varies with gravitational field strength. Everything that has physical substance has mass.
- GeneralClass 12All
What is 1 unit in grams?
In most contexts, 1 unit in grams equals 1 gram (1 g). However, "unit" can vary: Pharmaceutical dosing: varies by medication Nutrition: often 100 grams Atomic mass: 1 amu ≈ 1.66 × 10⁻²⁴ grams Always verify the specific definition used in your context.
- GeneralClass 12All
What is 100 grams called?
100 grams is called a hectogram (hg), though this term is rarely used in everyday language. More commonly, people simply say "100 grams" or "one-tenth of a kilogram" (0.1 kg).
- GeneralClass 12All
What is mass class 8?
In Class 8, mass concepts expand to include: Detailed difference between mass and weight Density calculations (Density = Mass/Volume) Conservation of mass in chemical reactions Gravitational effects on weight but not mass More complex problem-solving with mass units Students work with formulas and real-world applications of mass concepts.
- GeneralClass 12All
What is 100 units called?
100 units is called a hundred. If referring to a specific measurement: 100 meters = 1 hectometer 100 grams = 1 hectogram 100 of anything = 1 hundred (century in some contexts) The prefix "hecto-" means 100 in the metric system.
- GeneralClass 12All
Q: How many watts is 1 unit?
In electrical energy, 1 unit equals 1 kilowatt-hour (kWh), which means 1,000 watts used for 1 hour. This is not a measure of watts directly but of energy consumption. One kWh represents the energy consumed by a 1,000-watt device running for one hour or a 100-watt bulb running for 10 hours.
- GeneralClass 12All
Q: What is mass and volume?
Mass measures the amount of matter in an object (measured in kg or grams) and remains constant everywhere. Volume measures the space an object occupies (measured in cubic meters or liters) and can change with temperature and pressure. Together, they determine density (Density = Mass ÷ Volume).
- GeneralClass 12All
Q: What is mass in class 6?
In Class 6 science, mass is introduced as the amount of matter in an object. Students learn: Mass is measured in grams and kilograms Mass stays the same everywhere Difference between mass and weight How to use balances to measure mass Basic unit conversions It's taught as a fundamental property that doesn't change with location, unlike weight.
- GeneralClass 12All
Q: What is the mass of a 70kg person?
The mass of a 70 kg person is 70 kilograms. This mass remains constant regardless of location. On Earth, this person would weigh approximately 686 Newtons, but on the Moon, they would weigh about 114 Newtons while still having a mass of 70 kg.