Test: Class 9 General Science NCERT Based - 1

15 Questions MCQ Test Science & Technology for UPSC CSE | Test: Class 9 General Science NCERT Based - 1

Attempt Test: Class 9 General Science NCERT Based - 1 | 15 questions in 18 minutes | Mock test for UPSC preparation | Free important questions MCQ to study Science & Technology for UPSC CSE for UPSC Exam | Download free PDF with solutions

The amount of heat required to change one form of matters to other without changing the temperature is called:

Solution: Latent heat, energy absorbed or released by a substance during a change in its physical state (phase) that occurs without changing its temperature.


The force of attraction between the molecules of water is called:

Solution: Cohesion is the mutual attraction and sticking property of molecules. It is an intrinsic property in certain substances that is commonly caused by the structure and shape of its molecules, resulting in electrical attraction. Cohesion paves the way for surface tension, establishing a solid-like condition where, in low density or light, materials can be set. Cohesion is also known as cohesive force or cohesive attraction.


At what temperature water has the highest density?

Solution: When cooled from room temperature liquid water becomes increasingly dense, as with other substances, but at approximately 4°C (39 °F), pure water reaches its maximum density. As it is cooled further, it expands to become less dense.


Which one of the following solids is compressible?

Solution: A substance in solid state has high intermolecular forces and hence has the least intermolecular spaces. So if compression is done here, then there is little or negligible amount of space for the molecules to come further closer. Hence, they are the least compressible.


Brass is a:

  • Brass is an alloy made primarily of copper and zinc. The proportions of the copper and zinc are varied to yield many different kinds of brass. Basic modern brass is 67% copper and 33% zinc.

  • However, the amount of copper may range from 55% to 95% by weight, with the amount of zinc varying from 5% to 40%.2 Lead is commonly added to brass at a concentration of around 2%.

  • The lead addition improves the machinability of brass. However, significant lead leaching often occurs, even in brass that contains a relatively low overall concentration of lead. Uses of brass include musical instruments, firearm cartridge casing, radiators, architectural trim, pipes and tubing, screws, and decorative items.


Thermometer is an instrument that measures

Solution: A thermometer is an instrument that measures temperature. It can measure the temperature of a solid such as food, a liquid such as water, or a gas such as air. The three most common units of measurement for temperature are Celsius, Fahrenheit, and kelvin. The Celsius scale is part of the metric system.


Barometer measures:

  • Barometer, device used to measure atmospheric pressure. Because atmospheric pressure changes with distance above or below sea level, a barometer can also be used to measure altitude.

  • There are two main types of barometers: mercury and aneroid. In the mercury barometer, atmospheric pressure balances a column of mercury, the height of which can be precisely measured.


People normally put some Naphthalene balls in the box in which they keep clothes and winter blankets. After some weeks they find that there is no Naphthalene ball left in the box. Why does the Naphthalene ball disappear with time, without leaving any residue?

  • Sublimation is the transition from the solid phase to the gas phase without passing through an intermediate liquid phase.

  • This endothermic phase transition occurs at temperatures and pressures below the triple point. The term "sublimation" only applies to physical changes of state and not to the transformation of a solid into a gas during a chemical reaction.


If we burn graphite:

  • Graphite does not leave any residue when burnt in air because :- Graphite is completely made up of carbon, and when we burn it in ample amounts of oxygen it does not leave any residue behind.

  • Graphite is non flammable but can be burnt only in high temperatures. Graphite needs around 400 degrees to get burnt.It reduces when combined with air. it acts as a reducing agent.


Nanometer is an:

  • A nanometer (also "nanometre") is a unit of measurement used to measure length. One nanometer is one billionth of a meter, so nanometers are certainly not used to measure long distances.

  • Instead, they serve to measure extremely small objects, such as atomic structures or transistors found in modern CPUs. A single nanometer is one million times smaller than a millimeter. If you take one thousandth of a millimeter, you have one micrometer, or a single micron.

  • If you divide that micron by 1,000, you have a nanometer. Needless to say, a nanometer is extremely small.

  • Since integrated circuits, such as computer processors, contain microscopic components, nanometers are useful for measuring their size. In fact, different eras of processors are defined in nanometers, in which the number defines the distance between transistors and other components within the CPU.

  • The smaller the number, the more transistors that can be placed within the same area, allowing for faster, more efficient processor designs.


Which of the following statements is not true about an atom?

  • Atoms are not able to exist independently. All the elements on the far right side of the periodic table (inert or noble gas) atoms can exist independently because they all fulfil the octet rule. They do not need bond to become stable.

  • An atom is a fundamental piece of matter. (Matter is anything that can be touched physically.) Everything in the universe (except energy) is made of matter, and, so, everything in the universe is made of atoms.

  • An atom itself is made up of three tiny kinds of particles called subatomic particles: protons, neutrons, and electrons. The protons and the neutrons make up the center of the atom called the nucleus and the electrons fly around above the nucleus in a small cloud.

  • The electrons carry a negative charge and the protons carry a positive charge. In a normal (neutral) atom the number of protons and the number of electrons are equal. Often, but not always, the number of neutrons is the same, too.





The molecular formula of potassium nitrate is:


Molecular mass is defined as the:

  • Molecular mass is a number equal to the sum of the atomic masses of the atoms in a molecule. The molecular mass gives the mass of a molecule relative to that of the 12C atom, which is taken to have a mass of 12.

  • Molecular mass is a dimensionless quantity, but it is given the unit Dalton or atomic mass unit as a means of indicating the mass is relative to 1/12th the mass of a single atom of carbon-12.


Which of the following statements best explains why a closed balloon filled with helium gas rises in air?

Solution: Because the helium atoms are of lower mass than the average is molecules, the helium gas is less dense than air. The balloon thus weighs less than the air displaces by its volume.


Which of the following statements is incorrect about the structure of an atom?

1. The whole mass of an atom is concentrated in the nucleus

2. The atom is an indivisible particle

3. The atom as a whole is neutral

4. All the atoms are stable in their basic state

Choose the right option among the following:

  • The atomic structure of an element refers to the constitution of its nucleus and the arrangement of the electrons around it. Primarily, the atomic structure of matter is made up of protons, electrons, and neutrons.

  • The protons and neutrons make up the nucleus of the atom, which is surrounded by the electrons belonging to the atom. The atomic number of an element describes the total number of protons in its nucleus. Neutral atoms have equal numbers of protons and electrons. However, atoms may gain or lose electrons in order to increase their stability, and the resulting charged entity is called an ion.

  • Atoms of different elements have different atomic structures because they contain different numbers of protons and electrons. This is the reason for the unique characteristics of different elements.

Use Code STAYHOME200 and get INR 200 additional OFF
Use Coupon Code