GK: Class 12 General Q&A · Page 112
3,658 free answers on GK (General) for Class 12 students, across CBSE, ICSE and State boards.
Question & Answer
Questions
- GeneralClass 12All
How do you solve distance-rate-time (d = rt) problems?
This is another non-electrical formula (d = distance, r = rate/speed, t = time). However, the solving approach is similar to Ohm's Law: To find distance: d = r × t To find rate: r = d/t To find time: t = d/r The parallel with V = IR is clear: both involve three variables where knowing two allows you to calculate the third.
- GeneralClass 12All
How to calculate V_max value?
. V_max (maximum voltage) depends on the context: For AC circuits: V_max = V_rms × √2 ≈ V_rms × 1.414 Example: Household 120V AC has V_max ≈ 170V For DC circuits: V_max is simply the peak supply voltage For capacitors: V_max is the breakdown voltage rating Always refer to component specifications and circuit requirements when determining maximum volta
- GeneralClass 12All
What is the formula V = RW?
This appears to be a variation notation, but the standard formula is V = IR (voltage = current × resistance). If you're seeing V = RW in a specific context: W might represent current (though I is standard) It could be from a different field (like V = ωR for angular velocity) Always verify the context and variable definitions For basic circuit analysis, stick with V = IR as the standard form of Ohm's Law
- GeneralClass 12All
How do you find equivalent resistance in parallel (step-by-step)?
Write down the parallel resistance formula: 1/R_eq = 1/R₁ + 1/R₂ + 1/R₃ Find the reciprocal of each resistance value Add all the reciprocals together Take the reciprocal of the sum to get R_eq Example: For 6Ω and 3Ω in parallel: 1/R_eq = 1/6 + 1/3 = 1/6 + 2/6 = 3/6, so R_eq = 6/3 = 2Ω
- GeneralClass 12All
What is 240 volts equal to in practical terms?
240 volts is the standard household voltage in many countries including the UK, Australia, and most of Europe. In terms of electrical power: It's equivalent to 240 joules of energy per coulomb of charge It's twice the 120V standard used in North America It can deliver more power through the same current, making it efficient for high-power appliances like ovens, water heaters, and air conditioners
- GeneralClass 12All
How do you find current (I) with voltage (V) and resistance (R)?
Use Ohm's Law rearranged to solve for current: I = V/R Divide the voltage by the resistance to get current in amperes. Make sure voltage is in volts and resistance is in ohms for the correct result.
- GeneralClass 12All
How to find R_total with R₁ and R₂?
For series: R_total = R₁ + R₂ For parallel: Use one of these methods: General formula: 1/R_total = 1/R₁ + 1/R₂, then R_total = (R₁ × R₂)/(R₁ + R₂) Product-over-sum shortcut: R_total = (R₁ × R₂)/(R₁ + R₂) The product-over-sum method is particularly useful for just two resistors in parallel.
- GeneralClass 12All
What is the current if R = 50 ohms and V = 220 volts?
Using Ohm's Law (I = V/R): I = 220V ÷ 50Ω = 4.4 amperes This means a current of 4.4 amps flows through the 50-ohm resistor when 220 volts is applied across it. This is a common calculation for household electrical applications in many countries.
- GeneralClass 12All
How do you find equivalent resistance between two points?
Identify the configuration: Determine which resistors are in series and which are in parallel between the two points Simplify step by step: Start with the innermost combinations, calculate their equivalent resistance, and replace them with a single resistor Continue reducing: Keep simplifying until you have one resistance value between the two points Verify your work: Trace the current pat
- GeneralClass 12All
How do you calculate 4 resistors in parallel?
Use the parallel resistance formula with four terms: 1/R_eq = 1/R₁ + 1/R₂ + 1/R₃ + 1/R₄ Example: For 12Ω, 6Ω, 4Ω, and 3Ω in parallel: 1/R_eq = 1/12 + 1/6 + 1/4 + 1/3 = 1/12 + 2/12 + 3/12 + 4/12 = 10/12 R_eq = 12/10 = 1.2Ω
- GeneralClass 12All
What is equivalent resistance?
Equivalent resistance is the single resistance value that could replace a combination of resistors in a circuit while maintaining the same current flow. Think of it as simplifying multiple resistors into one "equivalent" resistor that has the same effect on the circuit. This concept helps analyze complex circuits more easily.
- GeneralClass 12All
What is equivalent resistance in parallel circuits?
In parallel circuits, the equivalent resistance is always less than the smallest individual resistor. The formula is: 1/R_eq = 1/R₁ + 1/R₂ + 1/R₃ + ... After calculating the sum of reciprocals, take the reciprocal of the result to find R_eq. This configuration provides multiple paths for current flow, reducing overall resistance.
- GeneralClass 12All
What is the formula for equivalent resistance in series?
For resistors connected in series, the equivalent resistance formula is: R_eq = R₁ + R₂ + R₃ + ... + Rₙ Simply add all the individual resistance values together. For example, three resistors of 10Ω, 20Ω, and 30Ω in series give an equivalent resistance of 60Ω.
- GeneralClass 12All
How do you find equivalent resistance in a circuit?
The method depends on how resistors are connected: Series circuits: Add all resistances together (R_total = R₁ + R₂ + R₃ + ...) Parallel circuits: Use the reciprocal formula (1/R_total = 1/R₁ + 1/R₂ + 1/R₃ + ...) Complex circuits: Break down the circuit into series and parallel sections, solve each part, then combine the results
- GeneralClass 12All
How do you solve for different variables using V = IR?
You can rearrange Ohm's Law to solve for any variable: To find voltage: V = I × R (multiply current by resistance) To find current: I = V ÷ R (divide voltage by resistance) To find resistance: R = V ÷ I (divide voltage by current) Simply identify which two values you know and use the appropriate formula to find the third.
- GeneralClass 12All
What do V and I represent in the formula V = IR?
In Ohm's Law (V = IR), V represents voltage (also called potential difference or electromotive force), measured in volts. I represents current, which is the flow of electric charge through a conductor, measured in amperes (amps). These variables work together with resistance (R) to describe how electricity behaves in a circuit.
- GeneralClass 12All
What is Ohm's Law?
Ohm's Law states that the voltage (V) across a conductor is directly proportional to the current (I) flowing through it, with resistance (R) being the constant of proportionality. The formula is V = IR, where V is voltage in volts, I is current in amperes, and R is resistance in ohms. This fundamental law helps you understand the relationship between these three electrical quantities in any circuit.
- GeneralClass 12All
Who got 500 out of 500 in 12th CBSE?
Several students have achieved perfect 500/500 scores in CBSE Class 12 boards over the years, though names change annually. These exceptional performers typically share traits: starting preparation early, maintaining consistent study routines, solving extensive practice papers, seeking conceptual clarity over rote learning, and managing time effectively during exams. Their success demonstrates that with dedicated effort, strategic preparation, and proper guidance, achieving top scores is poss
- GeneralClass 12All
What is the second name of kinematics?
Kinematics is sometimes called the "geometry of motion" because it describes motion mathematically without considering forces, similar to how geometry describes shapes without discussing their physical properties. Another term is "phoronomics," though this is rarely used today. In engineering contexts, kinematics overlaps with "dynamics" (when forces are excluded) and forms part of "mechanics," the broader study of motion and forces.
- GeneralClass 12All
Who is the father of kinematics?
Galileo Galilei is often called the father of kinematics for his pioneering work on motion in the 16th-17th centuries. He systematically studied falling bodies, projectile motion, and uniform acceleration, establishing that mathematics could describe natural phenomena. His experiments with inclined planes and careful observations laid the groundwork for Newton's laws. Galileo's approach of combining experimentation with mathematical analysis revolutionized physics and established kinematics a