Explanation: The energy value of food is measured in Calories (specifically kilocalories or kcal). One calorie is the amount of heat energy required to raise the temperature of one gram of water by one degree Celsius. Our bodies burn these calories to produce energy for movement, thinking, and maintaining body functions like heartbeat and breathing.
102
Stainless Steel is an alloy of Iron, Carbon, and:
✅ Correct Answer:Chromium
Explanation: Stainless Steel is an alloy of Iron, Carbon, and Chromium (usually at least 10.5%). The chromium reacts with oxygen to form a thin, invisible layer of chrome oxide on the surface, which prevents the steel from rusting and corroding. Nickel is also often added to improve corrosion resistance and durability.
103
Which vitamin is essential for healthy eyes?
✅ Correct Answer:Vitamin A
Explanation: Vitamin A is critical for maintaining good vision. It is a component of rhodopsin, a protein in the eyes that allows you to see in low light conditions. Deficiency in Vitamin A can lead to night blindness and Xerophthalmia (dry eyes). Foods rich in Vitamin A include carrots, sweet potatoes, and spinach.
104
Which metal is used in thermometers?
✅ Correct Answer:Mercury
Explanation: Mercury is used in thermometers because it remains liquid over a wide range of temperatures and expands uniformly with heat. Its silver color makes it easy to read against the scale. However, because mercury is toxic, modern digital thermometers or alcohol-based thermometers are becoming more common alternatives.
105
What is the freezing point of water?
✅ Correct Answer:0°C
Explanation: The freezing point of water is 0 degrees Celsius (32 degrees Fahrenheit) at standard atmospheric pressure. At this temperature, water changes from a liquid state to a solid state (ice). Interestingly, water is most dense at 4°C, which is why ice floats on water, allowing aquatic life to survive beneath frozen lakes in winter.
106
Which acid is found in Ant stings?
✅ Correct Answer:Formic Acid
Explanation: Formic Acid (Methanoic acid) is found in the venom of ant stings and bee stings. When an ant bites, it sprays this acid into the wound, causing a burning sensation, pain, and swelling. It is the simplest carboxylic acid. The name comes from the Latin word for ant, 'formica'. Baking soda is often used to neutralize the acid.
107
Optic Fibers work on the principle of:
✅ Correct Answer:Total Internal Reflection
Explanation: Optical fibers work on the principle of Total Internal Reflection. Light signals are transmitted through thin strands of glass or plastic. When light hits the boundary of the core and cladding at a specific angle, it is reflected entirely back into the core rather than passing out. This allows data to travel long distances with minimal loss.
108
Which is the smallest bone in the human body?
✅ Correct Answer:Stapes
Explanation: The Stapes (also known as the stirrup) is the smallest bone in the human body. It is located in the middle ear and is one of the three auditory ossicles that transmit sound vibrations from the eardrum to the inner ear. It is roughly the size of a grain of rice, measuring only about 3 x 2.5 millimeters.
109
The chemical formula of Ozone is:
✅ Correct Answer:O3
Explanation: Ozone is an inorganic molecule with the chemical formula O3. It is a pale blue gas with a distinctively pungent smell. It is an allotrope of oxygen that is much less stable than the diatomic allotrope O2. While beneficial in the stratosphere (ozone layer), it is a pollutant at ground level and can cause respiratory problems.
110
Which planet is the largest in our Solar System?
✅ Correct Answer:Jupiter
Explanation: Jupiter is the largest planet in our Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets combined. It is known for its Great Red Spot, a giant storm bigger than Earth. It has a strong magnetic field and dozens of moons, including Ganymede, the largest moon in the solar system.
111
Which lens is used to correct Long-sightedness (Hypermetropia)?
✅ Correct Answer:Convex Lens
Explanation: A Convex Lens is used to correct Hypermetropia (long-sightedness), where a person can see distant objects clearly but close ones are blurry. This condition occurs when the image focuses behind the retina. The convex lens converges the light rays before they enter the eye, moving the focal point forward onto the retina.
112
What is the most abundant gas in the Earth's atmosphere?
✅ Correct Answer:Nitrogen
Explanation: Nitrogen is the most abundant gas in Earth's atmosphere, making up about 78% of the air we breathe. Oxygen makes up about 21%, and Argon consists of nearly 1%. Nitrogen is essential for life as it is a key component of amino acids (proteins) and DNA, although most organisms cannot use it directly from the air.
113
Who discovered Penicillin?
✅ Correct Answer:Alexander Fleming
Explanation: Alexander Fleming discovered Penicillin in 1928. It was the world's first true antibiotic, derived from the mold Penicillium notatum. This discovery revolutionized medicine by providing an effective treatment for bacterial infections that were previously fatal. Fleming observed that the mold killed the bacteria growing around it in a petri dish.
114
Which part of the body is affected by Pneumonia?
✅ Correct Answer:Lungs
Explanation: Pneumonia is an infection that inflames the air sacs (alveoli) in one or both lungs. The air sacs may fill with fluid or pus, causing cough with phlegm, fever, chills, and difficulty breathing. It can be caused by bacteria, viruses, or fungi. It is a serious condition, especially for infants and the elderly.
115
Which gas is mainly responsible for Global Warming?
✅ Correct Answer:Carbon Dioxide
Explanation: Carbon Dioxide (CO2) is the primary greenhouse gas contributing to global warming. It is released through the burning of fossil fuels (coal, oil, gas), deforestation, and industrial processes. It traps heat in the atmosphere, leading to a rise in Earth's average temperature, melting ice caps, and changing weather patterns.
116
The process of coating Iron with Zinc to prevent rusting is called:
✅ Correct Answer:Galvanization
Explanation: Galvanization is the process of applying a protective zinc coating to steel or iron to prevent rusting. The zinc acts as a sacrificial anode; it corrodes first, protecting the underlying metal. This is commonly used in construction materials, pipes, and car bodies to extend their lifespan in outdoor environments.
117
Which instrument is used to measure Humidity?
✅ Correct Answer:Hygrometer
Explanation: A Hygrometer is an instrument used to measure the amount of water vapor (humidity) in the atmosphere, soil, or confined spaces. High humidity can make hot temperatures feel more uncomfortable, while low humidity can cause dryness. There are various types, including hair hygrometers and digital sensors.
118
The chemical formula for Common Sugar (Sucrose) is:
✅ Correct Answer:C12H22O11
Explanation: The chemical formula for Sucrose (common table sugar) is C12H22O11. It is a disaccharide composed of two monosaccharides: glucose and fructose. It is extracted primarily from sugarcane and sugar beet. When consumed, the body breaks it down into glucose and fructose to be used as energy.
119
Which of the following is a good conductor of electricity?
✅ Correct Answer:Copper
Explanation: Copper is a good conductor of electricity because it has free electrons that can move easily through the material. This allows electric current to flow with very little resistance. That is why copper is widely used in electrical wiring, motors, and electronics. Glass, plastic, and rubber are insulators.
120
What is the average heartbeat rate of a healthy adult per minute?
✅ Correct Answer:60-100
Explanation: The normal resting heart rate for adults ranges from 60 to 100 beats per minute. A lower heart rate at rest generally implies more efficient heart function and better cardiovascular fitness. For example, a well-trained athlete might have a normal resting heart rate closer to 40 beats per minute.