GK: Class 12 General Q&A · Page 86
3,658 free answers on GK (General) for Class 12 students, across CBSE, ICSE and State boards.
Question & Answer
Questions
- GeneralClass 12All
What is my mass if I weigh 70 kg?
Your mass is 70 kilograms. When you step on a bathroom scale showing 70 kg, you're measuring mass, not technically weight. Your actual weight in proper units is approximately 686 Newtons on Earth.
- GeneralClass 12All
What is my mass if I weigh 40 kg?
Your mass is 40 kilograms. Despite saying "weigh 40 kg" in everyday language, you're referring to mass. Your weight in scientific units would be approximately 392 Newtons on Earth.
- GeneralClass 12All
What is my mass if I weigh 100 kg?
If someone says they "weigh 100 kg," their mass is 100 kilograms. In scientific terms, their actual weight is approximately 980 Newtons. The everyday use of "weigh" when referring to kilograms actually means mass.
- GeneralClass 12All
What is the mass of 45 kg?
The mass is 45 kilograms by definition. This is a straightforward statement - 45 kg is already a measurement of mass. On Earth, this mass would experience a weight of approximately 441 Newtons.
- GeneralClass 12All
What is a normal body mass in kg?
Normal body mass varies by height, age, and sex, but general ranges are: Adult women: 50-70 kg Adult men: 60-85 kg Children: Varies significantly with age A better indicator is Body Mass Index (BMI), which considers both height and weight. A healthy BMI falls between 18.5 and 24.9.
- GeneralClass 12All
Is 40kg heavy for a 12 year old?
40 kg is within the normal range for a 12-year-old, though it depends on height and build. According to growth charts: For 12-year-old girls: average is 40-45 kg For 12-year-old boys: average is 38-43 kg Individual variation is normal, and healthy weight depends more on overall health and development than a specific number.
- GeneralClass 12All
Is 100 grams one kg?
No, 100 grams is one-tenth of a kilogram (0.1 kg). You need 1,000 grams to equal one kilogram. This is a common misconception, but remember that the prefix "kilo-" means 1,000.
- GeneralClass 12All
How many 500g are in 3kg?
There are 6 units of 500g in 3 kg. Calculation: 3 kg = 3,000 g ÷ 500 g = 6
- GeneralClass 12All
How many 30 grams are in 1kg?
There are approximately 33.33 units of 30 grams in 1 kg. Calculation: 1,000 g ÷ 30 g = 33.33 This means you can fit 33 complete 30-gram portions in one kilogram.
- GeneralClass 12All
What is 1 stone in kg?
One stone equals 6.35 kilograms. The stone is a British imperial unit of mass still used in the UK and Ireland for measuring body weight. For example, 10 stone = 63.5 kg.
- GeneralClass 12All
What is the mass of a 5kg object?
The mass of a 5 kg object is simply 5 kilograms. This might seem like a circular answer, but it emphasizes that mass is an intrinsic property. Whether on Earth, the Moon, or in space, this object's mass remains 5 kg, though its weight would vary.
- GeneralClass 12All
Why do we calculate refractive index?
We calculate refractive index for numerous practical reasons: Material identification: Different substances have unique RI values Quality control: Verifying purity of liquids (honey, oils, beverages) Lens design: Engineering glasses, cameras, microscopes, telescopes Gemology: Identifying and valuing precious stones Medical diagnostics: Analyzing blood, ur
- GeneralClass 12All
Is refractive index only for light?
While most commonly applied to light (visible electromagnetic radiation), refractive index principles apply to all electromagnetic waves, including: Radio waves Microwaves Infrared radiation Ultraviolet radiation X-rays (though they behave differently) The concept can even extend to other wave phenomena like sound waves in some contexts, though the term "refractive index" is predominantly used for electrom
- GeneralClass 12All
What is the refractive index according to class 12th?
According to Class 12 physics curriculum, the refractive index is defined as: "The ratio of the speed of light in vacuum to the speed of light in the medium" Concepts covered include: Formula: n = c/v Snell's law: n₁ sin θ₁ = n₂ sin θ₂ Absolute and relative refractive index Laws of refraction Critical angle and total internal reflection Applications in lenses and optical instruments</
- GeneralClass 12All
How is sin to cos?
The relationship between sine and cosine is given by the complementary angle identity: sin θ = cos(90° - θ) cos θ = sin(90° - θ) Also, they're related by the Pythagorean identity: sin²θ + cos²θ = 1 To convert between them, you can use: cos θ = √(1 - sin²θ) or sin θ = √(1 - cos²θ)
- GeneralClass 12All
What are the two laws of refractive index?
The two fundamental laws of refraction (also called Snell's laws) are: First Law: The incident ray, the refracted ray, and the normal to the interface at the point of incidence all lie in the same plane. Second Law: For a given pair of media and for light of a given wavelength, the ratio of the sine of the angle of incidence to the sine of the angle of refraction is constant. This constant is the refractive index: sin i/sin r = n₂₁ (c
- GeneralClass 12All
What is the value of sin 720°?
Sin 720° = 0 Since sine has a period of 360°, sin 720° = sin(720° - 2×360°) = sin 0° = 0. Completing two full rotations brings you back to the starting position.
- GeneralClass 12All
What is sec 270° equal to?
Sec 270° is undefined because sec θ = 1/cos θ, and cos 270° = 0. Division by zero is undefined in mathematics.
- GeneralClass 12All
What is the exact value of sin 120 degrees?
Sin 120° = √3/2 (approximately 0.866) This can be found using the identity: sin 120° = sin(180° - 60°) = sin 60° = √3/2
- GeneralClass 12All
What is the square root of 720 simplified?
√720 = 12√5 Simplification: √720 = √(144 × 5) = √144 × √5 = 12√5 ≈ 26.83