1. Which one of the following is a conventional energy source ?
Correct : A
Explanation: Conventional energy sources are non-renewable sources of energy which are finite. Example : Coal, Petroleum, Natural gas, Nuclear energy, Fossil fuels, Biomass, Electricity.
2. During Solar eclipse
Correct : C
Explanation: A solar eclipse happens when the moon passes between the Earth and the sun, blocking the sun's rays from reaching Earth. This can either be a partial or total eclipse.
3. The scientist who first discovered that the Earth revolves round the Sun was
Correct : D
Explanation: Nicolaus Copernicus was the first scientist to discover that the Earth revolves around the Sun. In 1512, he proved that the Earth revolves around the Sun in the heliocentric solar system.
4. Density of water is
Correct : B
Explanation: Water's density is greatest at around 4° Celsius (39.2° Fahrenheit). This is because at this temperature, two opposing effects are in equilibrium. When the temperature of water increases from 0° to 4° Celsius, some of the H-bonds break and the molecules come closer together. This increases the density because the volume decreases. However, above 4° Celsius, the kinetic energy of the molecules increases, which leads to an increase in volume and a decrease in density.
5. Ball Pen functions on which one of the following principle ?
Correct : A
Explanation: Ballpoint pens, also known as ball pens, work on the principle of: Capillary action, Rolling friction, Surface tension. A ballpoint pen has a small metal ball at the tip that rotates freely.As the pen moves across the paper, the ball rotates, picking up ink from the cartridge and leaving it on the paper.
The capillary action is due to the surface tension.
6. When ice melts, its
Correct : B
Explanation: When ice melts, its volume decreases. This is because ice is less dense than water. This means that a given mass of water will take up less space than the same mass of ice.
7. Sound wave cannot pass through above
Correct : D
Explanation: Sound waves cannot pass through a vacuum. A vacuum is a space that is devoid of air. Sound waves require a material medium for their propagation.
8. Device used to measure very high temperature is
Correct : A
Explanation: A pyrometer is a device used to measure very high temperatures. It measures the radiation of an object without the need for contact. Pyrometers are often used to measure the temperature of furnaces.
9. The image formed on the retina of a human eye is
Correct : A
Explanation: The image formed on the retina of the human eye is real and inverted.The human eye's lens is convex, which is why the image formed on the retina is real and inverted. The maximum magnification of the human eye is at the near point.
10. A fuse wire is made of an alloy of
Correct : B
Explanation: Fuse wire is made of an alloy of tin and lead because:
Low melting point: It's important that the device melts without heating so as not to produce fires or to heat nearby terminals or cables.
High resistance: The material should have high resistance and low boiling point.
11. A radar beam consists of
Correct : A
Explanation: Microwaves are electromagnetic waves with high wavelengths and low frequencies. They are used in radar to detect objects.
Radar works by transmitting a focused pulse of microwave energy at an object. The microwaves reflect back and are detected by a receiver in the radar. The frequency of the reflected waves is used to determine the speed and distance of the objects.
12. The gas used in a refrigerator is
Correct : A
Explanation: When the gas expand the heat of gas started cool down.
13. Radioactive substance used in dating geological object is
Correct : C
Explanation: Radiocarbon dating, also known as carbon-14 dating, is a scientific method for determining the age of organic materials. It can accurately date materials up to 60,000 years old.
14. Butter is a colloid formed when
Correct : A
Explanation: Butter is a colloid ( mixture of two or more substances that are not chemically combined) formed when water is dispersed (to separate )in fat.
15. Which one of the following is not a chemical change ?
Correct : B
Explanation: A chemical change is a process that causes a new substance to form. Physical changes don't create a new substance. For example, melting is a physical change because solid ice and liquid water are the same chemical compound.
16. Which one of the following is the softest metal ?
Correct : D
Explanation: Sodium is a soft metal that it can be cut with a knife.The strong cohesive forces between the atoms determine a metal's hardness. Sodium have very weak cohesive interactions between their atoms.
17. Dry ice is
Correct : A
Explanation: Dry ice is the solid form of carbon dioxide (CO2). It's called dry ice because it doesn't melt into a liquid when heated, but instead turns directly into a gas. This process is called sublimation.
18. Glass is best described as a
Correct : C
Explanation: Glass is best described as a supercooled liquid. Glass is a transparent, amorphous solid that doesn't form a crystalline structure. Instead, it forms an amorphous solid that allows molecules in the material to continue to move. The raw material of glass is made from three ingredients: sand, limestone, and soda ash.
19. In the heavy vehicles, diesel is used as fuel because
Correct : A
Explanation: Diesel is used in heavy vehicles because it has high power and torque, is efficient, and is cheaper than petrol.
20. The natural rubber is a polymer of
Correct : A
Explanation: Natural rubber is a polymer of isoprene. Isoprene is also known as 2-methyl-1,3-butadiene. It is a colorless, volatile liquid with two double bonds.
21. What is the pH of pure water ?
Correct : B
Explanation: Pure water has a pH of 7, which is neutral. This means that pure water is neither acidic nor basic.
22. The main constituent of Vinegar is
Correct : C
Explanation: The main constituent of vinegar is acetic acid (CH3COOH).Vinegar has a sour taste and pungent aroma. It is used as a preservative or as an acid for cooking.
23. The metal present in Vitamin B12 is
Correct : C
Explanation: The metal present in vitamin B12 is cobalt. Vitamin B12 is also known as cobalamin. It is the largest and most complex vitamin.
24. Vermicompost is a/an
Correct : B
Explanation: Vermicompost is a nutrient-rich organic fertilizer and soil conditioner. It's made by using worms to break down organic matter, like food waste and manure. The process is called vermicomposting.
25. Suicidal bag of cell is
Correct : D
Explanation: Lysosomes are called the "suicide bags" of a cell because they contain hydrolytic enzymes that can destroy the cell. The enzymes break down waste materials, foreign material, and cellular debris. If a cell is damaged or dies, the lysosomes burst and release the enzymes. The enzymes then digest the cell, leading to cell death.