GK: Class 12 General Q&A · Page 130
3,658 free answers on GK (General) for Class 12 students, across CBSE, ICSE and State boards.
Question & Answer
Questions
- GeneralClass 12All
What is the resistivity of a conductor?
Conductors have very low resistivity values, typically in the range of 10⁻⁸ to 10⁻⁶ Ω·m. Common examples include: Silver: 1.59 × 10⁻⁸ Ω·m (best conductor) Copper: 1.68 × 10⁻⁸ Ω·m Gold: 2.44 × 10⁻⁸ Ω·m Aluminum: 2.82 × 10⁻⁸ Ω·m The lower the resistivity, the bett
- GeneralClass 12All
11. What is the resistivity of steel?
The resistivity of steel varies depending on its composition: Carbon steel: approximately 1.43 × 10⁻⁷ Ω·m Stainless steel: approximately 6.9 × 10⁻⁷ to 1.0 × 10⁻⁶ Ω·m Steel has higher resistivity than pure metals like copper (1.68 × 10⁻⁸ Ω·m) or aluminum (2.82 × 10⁻⁸ Ω·m), making it a less efficient conductor but still suitable for structu
- GeneralClass 12All
10. What is the resistivity of air?
The resistivity of air is approximately 1.3 × 10¹⁶ to 3.3 × 10¹⁶ Ω·m under normal conditions. This extremely high value makes air an excellent insulator. However, resistivity decreases significantly in humid conditions or when air becomes ionized (such as during lightning), allowing current to flow more easily.
- GeneralClass 12All
What materials have high resistivity?
Materials with high resistivity are typically insulators: Rubber: ~10¹³ Ω·m Glass: ~10¹⁰ to 10¹⁴ Ω·m Teflon: ~10²³ Ω·m uartz: ~10¹⁶ Ω·m Air/vacuum: ~10¹⁶ Ω·m Pure water: ~2.5 × 10⁵ Ω·m These
- GeneralClass 12All
What is the SI unit of resistivity?
The SI unit of resistivity is ohm-meter (Ω·m). Sometimes you'll also see it written as ohm-centimeter (Ω·cm) for convenience, especially when dealing with very small values. To convert: 1 Ω·m = 100 Ω·cm.
- GeneralClass 12All
What is resistivity and conductivity?
Resistivity and conductivity are inverse properties. Conductivity (σ) measures how easily a material allows electric current to flow, while resistivity (ρ) measures how much it resists current flow. The relationship is: σ = 1/ρ or ρ = 1/σ Conductivity is measured in siemens per meter (S/m). Good conductors have high conductivity and low resistivity, while insulators have low condu
- GeneralClass 12All
How is resistivity related to resistance?
Resistivity and resistance are related through the euation: R = ρL/A This shows that resistance is directly proportional to both resistivity and length, but inversely proportional to cross-sectional area. If you double the length of a wire, you double its resistance. If you double its cross-sectional area, you halve its resistance. The resistivity (ρ) acts as the proportionality constant linking these uantities.
- GeneralClass 12All
What is resistivity vs. resistance?
Resistance is the opposition to current flow in a specific object and depends on its dimensions (length and cross-sectional area). It's measured in ohms (Ω). Resistivity is an intrinsic material property independent of size or shape. It's measured in ohm-meters (Ω·m). Think of it this way: resistivity tells you about the material itself, while resistance tells you about a particular piece of that material. A long, thin coppe
- GeneralClass 12All
How to calculate resistivity?
To calculate resistivity, follow these steps: Measure the resistance (R) of the material using an ohmmeter Measure the length (L) of the conductor Calculate the cross-sectional area (A) of the conductor Apply the formula: ρ = RA/L Example: If a wire has resistance of 2 Ω, length of 5 meters, and cross-sectional area of 0.001 m², then ρ = (2 × 0.001)/5 = 0.0004 Ω·m
- GeneralClass 12All
What is the formula for resistivity with E (electric field)?
The formula relating resistivity to electric field is: ρ = E/J Where: ρ = resistivity E = electric field strength (volts per meter, V/m) J = current density (amperes per suare meter, A/m²) This formula shows that resistivity euals the electric field divided by the current density, providing another way to understand how materials resist current flow.
- GeneralClass 12All
What is the resistivity formula and unit?
The resistivity formula is: ρ = RA/L Where: ρ (rho) = resistivity R = resistance in ohms (Ω) A = cross-sectional area in suare meters (m²) L = length in meters (m) The SI unit of resistivity is ohm-meter (Ω·m). This unit represents the resistance of a material with a cross-sectional area of one suare meter and a length of one meter.
- GeneralClass 12All
What is resistivity?
Resistivity is a fundamental property of materials that measures how strongly they resist the flow of electric current. It indicates how difficult it is for electrons to move through a material. Unlike resistance, which depends on the size and shape of an object, resistivity is an intrinsic property that remains constant for a given material at a specific temperature. Materials with low resistivity (like copper and silver) are good conductors, while those with high resistivity (like rubber an
- GeneralClass 12All
How do you write a cheque amount in words
Writing a cheque amount in words requires precision and follows specific conventions to prevent fraud and ensure clarity. Start by writing the amount from the extreme left edge of the words line, using the full written form of the number—for example, "Five thousand seven hundred fifty only" for 5,750. The word "only" at the end is crucial as it legally indicates the amount is complete with no additional paise or cents. Draw a line from the end of your written amount to the right edge of
- GeneralClass 12All
How is 1100 written in words
The number 1100 is written as "one thousand one hundred" in words, following standard English conventions. There's no "and" between "thousand" and "one hundred" in American English, though British English traditionally includes it as "one thousand and one hundred." Both forms are acceptable within their respective conventions, but American business and financial documentation typically uses the more concise format without "and." In everyday speech, you'll often hear 1100 referred to a
- GeneralClass 12All
How do you write 6500 in words
The number 6500 is written as "six thousand five hundred" in words. This straightforward number combines six thousands and five hundreds with no additional ones or tens. In American English, there's no "and" between "thousand" and "five hundred," keeping the written form concise and clear for business and financial documents, though British English speakers might include "and" as "six thousand and five hundred." When using this amount in practical contexts like cheques, invoices, or c
- GeneralClass 12All
How do you write 3500 00 in words for a cheque
For a cheque, 3500.00 is written as "Three thousand five hundred and 00/100" or "Three thousand five hundred only" depending on your regional banking conventions. The American system often uses the fractional format (00/100) to precisely indicate zero cents, while other regions simply use "only" to confirm the amount contains no paise or fractional currency. Both formats are legally acceptable and widely recognized by banking institutions. Proper cheque writing technique requires care
- GeneralClass 12All
How much is 8000.00 in words
The amount 8000.00 is written as "eight thousand and 00/100" on a cheque, or simply "eight thousand only" in general formal writing. The ".00" indicates zero cents or paise, meaning this is an exact whole number with no fractional currency. On checks specifically, American convention often writes decimals as fractions (00/100, representing zero cents out of 100), while in other contexts or regions, you'd simply write "only" to indicate completeness. When writing this amount on formal
- GeneralClass 12All
Which country code is 052
The prefix 052 is not a country calling code in the international telephone system. International country codes range from 1 to 999 and always begin with a plus sign (+) when dialed internationally, such as +1 for the United States/Canada, +44 for the United Kingdom, or +91 for India. The sequence 052 appears to be a partial or local area code, which has different meanings depending on the country you're calling from or within. In several countries, 052 serves as a domestic area code
- GeneralClass 12All
What is 88 called in English
The number 88 is called "eighty-eight" in English, with a hyphen connecting the two parts as required by standard grammar rules for all compound numbers from twenty-one through ninety-nine. This hyphenation shows that "eighty" and "eight" work together as a single numerical unit representing 8 tens and 8 ones. Beyond its basic numerical designation, 88 holds cultural significance in various contexts that might be relevant depending on usage. In Chinese culture, 88 is considered extrem
- GeneralClass 12All
What is this number 1000000000000000000000000
This number is called "one septillion" in American English or "one quadrillion" in British English—the difference stems from the two distinct systems used to name large numbers. In the short scale system (used in the United States and modern British English), every new word represents a thousand times the previous value, making this 24-zero number a septillion (1,000^8). In the long scale system (historically used in British English and still used in many European countries), new number