Everyday Science

A blood alcohol concentration (BAC) above 0.40% (0.41) is typically life-threatening and can result in death due to respiratory failure or coma. Lower levels cause intoxication but are less likely to be fatal.

Acupuncture is a traditional medical treatment that involves pricking the body with fine needles to relieve pain and treat various conditions. This method does not involve drugs, herbs, or electric shocks as primary treatments.

Presbyopia is corrected using bifocal lenses, which have two distinct optical powers to help focus on both near and distant objects. Convex lenses are used for hypermetropia, concave for myopia, and cylindrical lenses for astigmatism.

A gas heater primarily transfers heat to the surrounding air through convection, where warm air rises and circulates, distributing heat effectively. Radiation and conduction are less significant in this context, and environmental pressure is unrelated to heat transfer.

The sun emits a spectrum of light, but the brightest color perceived by the human eye from sunlight is yellow-green, which corresponds to the peak sensitivity of human vision and the sun's emission spectrum.

Biogas is considered a non-conventional source of energy because it is renewable and derived from organic waste, unlike coal which is a conventional fossil fuel. Algae can be a source of biofuel but is less commonly categorized as a direct energy source compared to biogas.

Green leaves appear green because they reflect green light and absorb other colors. Under red light, there is no green light to reflect, so the leaves absorb the red light and appear very dark or black to the eye.

Vitamin B12 contains cobalt as a central metal ion in its structure, which is essential for its biological activity. The other options do not contain cobalt.

Phosphorus is the substance commonly used in match sticks because it ignites easily when struck against a rough surface, enabling the match to light.

Hydrogen has the highest fuel value (energy content per unit mass) compared to charcoal and gasoline, making it the most energy-dense fuel among the options.

Carbohydrates are primarily composed of sugars and starches. Sugars are simple carbohydrates, while starches are complex carbohydrates, both constituting the carbohydrate group.

The tarsal bones are a group of seven bones located in the foot, forming the ankle and part of the foot's structure. Therefore, the correct answer is 'Foot'.

The dielectric constant of water at room temperature is approximately 80, which makes option C correct. This value reflects water's high polarity and ability to reduce the electric field between charges.

EEG (Electroencephalogram) is a diagnostic tool used to measure electrical activity in the brain, making it useful for diagnosing brain-related ailments such as epilepsy and other neurological disorders.

The plague is primarily spread by fleas that infest rats, making rats the main carriers of the disease. This is why option C, 'Rat', is the correct answer.

Sodium thiosulphate is commonly used as a fixer in photography to dissolve unexposed silver halide crystals from the photographic film or paper, making the image permanent and light-resistant.

Meat primarily consists of proteins and fats and contains negligible carbohydrates, unlike rice, potato, and milk which all contain carbohydrates. Therefore, meat is the correct answer as it does not contain carbohydrates.

Silicon is often called the 'earth maker' because it is a major component of the Earth's crust, forming many minerals and rocks. The other elements listed do not have this specific association.

The most common form of color blindness is red-green color blindness, where individuals have difficulty distinguishing between red and green hues. The other options do not represent typical color blindness distinctions.

BRT stands for Bus Rapid Transit, which is a high-quality bus-based transit system that delivers fast, comfortable, and cost-effective services at metro-level capacities.

A disease always has a cause, which can be a pathogen, genetic factor, or environmental influence. The other options are not always true: not all diseases have a cure, germs are not the cause of all diseases, and a disease does not always have a patient (e.g., theoretical or experimental contexts).

Excessive intake of Vitamin A can lead to toxicity that affects the kidneys, causing kidney damage. Overdose of proteins or vitamins B and C is less commonly associated with kidney disease.

Football is a high-intensity sport involving continuous running and physical exertion, leading to the highest calorie consumption among the options listed. Cricket, golf, and billiards involve less intense physical activity and thus burn fewer calories.

Atmospheric pressure at sea level is standardly defined as 760 mm of mercury (mmHg). This is the commonly accepted value for atmospheric pressure under normal conditions.

The frequency of a tuning fork is determined using a sonometer, which measures the frequency of vibrating strings and can be used to compare with the tuning fork's frequency.