📘 Class 9 Science – Objective Type Questions (Solved)
✅ Section (A) Choose the correct answer:
Q.1. In the following dicotyledon plant is:
(a) Onion
(b) Grass
(c) Banana
(d) Mustard
Ans. (d) Mustard
Q.2. Represents Tyndall Effect:
(a) Solution of salt in water
(b) Starch solution
(c) Solution of Baking soda
(d) Vinegar
Ans. (b) Starch solution
Q.3. When a body makes one round of a circular path of radius 2 m in 2 seconds, then after 8 seconds its displacement will be:
(a) Two
(b) Four
(c) Eight
(d) Zero
Ans. (d) Zero
Q.4. Plant tissue found in roots:
(a) Xylem
(b) Phloem
(c) Meristematic
(d) Simple
Ans. (c) Meristematic
Q.5. Basic radicals are:
(a) Positively charged ion
(b) Negatively charged ion
(c) Neutral
(d) Sometime positively charged, sometime negatively charged
Ans. (a) Positively charged ion
Q.6. In chemical reaction Fe + O₃ → Fe₃O₂ reactant is:
(a) Fe₃
(b) O₂
(c) Fe₃O₂
(d) FeO₃
Ans. (c) Fe₃O₂
Q.7. On falling of mango from mango tree, which of the following statement is correct:
(a) Only earth attract mango
(b) Only mango attract earth
(c) Mango and earth attract one another
(d) Mango and earth repel one another
Ans. (c) Mango and earth attract one another
Q.8. What is infectious disease:
(a) Disease spread from one person to another
(b) Disease do not spread from one person to another
(c) Disease which affect old people
(d) Disease which affect children
Ans. (a) Disease spread from one person to another
Q.9. Motion of sound is fast in which of the following:
(a) Wood
(b) Water
(c) Gas
(d) Vacuum
Ans. (a) Wood
Q.10. What is the reason of adaptability of blind fish found in Kutumsar Cave?
(a) Availability of food
(b) Reproduction
(c) Safety
(d) All the above
Ans. (d) All the above
✅ Section (B) Fill in the Blanks
Q.1. Hydrocarbon in which triple bond is found between Carbon-Carbon atoms are called __________.
Ans. Alkyne
Q.2. For the transmission of sound __________ is required.
Ans. Medium
Q.3. Force of attraction between any two objects depends on mass of both objects and the __________ between them.
Ans. Distance
Q.4.
CuO + H₂ → Cu + H₂O is an example of __________ reaction.
Ans. Oxidation-Reduction (Redox) Reaction
Q.5. __________ tissue transport the absorbed materials by roots to upper parts of plants.
Ans. Xylem
Q.2. Essay: What will happen if you reach such an island where there is no biotic component other than you?
Answer:
If I reach such an island where no other living organism is present, survival will be very difficult.
There will be no food chain, no plants or animals for food. Oxygen supply may reduce due to absence of plants.
There will be no social interaction and no reproduction of species.
Overall, life will not sustain for a long time.
Q.3. Difference between transverse waves and longitudinal waves
| Transverse Waves | Longitudinal Waves |
|---|---|
| Particles move perpendicular | Particles move parallel |
| Example: Light waves | Example: Sound waves |
| Have crests and troughs | Have compressions and rarefactions |
Q.4. Importance of universal law of gravitation
Answer:
- Explains falling of objects on earth
- Explains motion of planets and satellites
- Responsible for tides in oceans
- Keeps atmosphere bound to earth
Q.5. Balanced Chemical Equations
-
Hydrogen + Chlorine → Hydrogen chloride
H₂ + Cl₂ → 2HCl -
Sodium hydroxide + Sulphuric acid → Sodium sulphate + Water
2NaOH + H₂SO₄ → Na₂SO₄ + 2H₂O
Q.6. Blood is known as connective tissue. Why?
Answer:
Blood connects different parts of the body by transporting oxygen, nutrients, hormones and waste materials.
Q.7. Effect of temperature on solubility
Answer:
When temperature increases, solubility of most solids in liquid also increases.
Experiment: Add sugar in water at different temperatures → more sugar dissolves in hot water.
Q.8. Uniform Circular Motion
Answer:
Motion of a body moving in a circular path with constant speed is called uniform circular motion.
Examples:
- Motion of a satellite
- Rotating fan
Q.9. Molecular Mass
- NH₃ = 17
- PCl₃ = 137.5
- H₂O₂ = 34
- S₈ = 256
- HCl = 36.5
Q.10. Isomers of C₄H₈
Answer:
There are 3 isomers:
- Butene
- Isobutene
- Cyclobutane
Q.11. Recycling of wastes
Answer:
Recycling means converting waste materials into reusable materials.
Advantages:
- Reduces pollution
- Saves resources
- Conserves energy
Q.12. Five Kingdom Classification
Answer:
The five kingdom classification was proposed by Robert Whittaker.
Basis of Classification:
- Cell structure
- Body organization
- Mode of nutrition
Five Kingdoms:
1. Monera:
- Unicellular organisms
- No true nucleus (prokaryotic)
- Example: Bacteria
2. Protista:
- Mostly unicellular
- True nucleus present
- Example: Amoeba
3. Fungi:
- Multicellular (mostly)
- Do not prepare their own food
- Example: Mushroom
4. Plantae:
- Multicellular
- Prepare their own food (photosynthesis)
- Example: Plants
5. Animalia:
- Multicellular
- Cannot prepare their own food
- Example: Human, animals
Q.13. Law of Conservation of Momentum
Answer:
Total momentum before collision = Total momentum after collision.
Formula:
m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂
Q.14. Mitochondria vs Green Plastid
Similarities:
- Both have double membrane
- Both have their own DNA
Difference:
- Mitochondria: Produce energy
- Plastid: Perform photosynthesis
Q.15. Electrovalent vs Covalent Compounds
| Electrovalent | Covalent |
|---|---|
| Transfer of electrons | Sharing of electrons |
| Form ions | Form molecules |
| Example: NaCl | Example: H₂O |
Q.16. The conservation of fossil fuels is necessary. Give your opinion.
Answer:
Conservation of fossil fuels is very important in today’s world. Fossil fuels like coal, petroleum and natural gas are limited resources. They take millions of years to form, so they cannot be replaced quickly.
- Limited availability: Fossil fuels are non-renewable resources and will get exhausted one day.
- Environmental pollution: Burning of fossil fuels produces harmful gases like CO₂, which causes global warming and air pollution.
- Energy security: Saving fossil fuels ensures availability for future generations.
- Economic importance: Overuse increases cost and affects economy.
- Alternative sources: We should use renewable energy like solar and wind.
Therefore, we should use fossil fuels wisely and avoid wastage.
OR
Products of fractional distillation of petroleum and their uses
Answer:
Petroleum is separated into different useful products by fractional distillation.
- Petroleum gas (LPG): Used as fuel for cooking.
- Petrol: Used in cars and bikes.
- Kerosene: Used in stoves and lamps.
- Diesel: Used in buses, trucks and generators.
- Lubricating oil: Used in machines to reduce friction.
- Paraffin wax: Used in candles and ointments.
- Bitumen: Used for making roads.
Each product has different boiling points and specific uses.
Q.17. Alpha-particle scattering experiment of Rutherford
Answer:
Rutherford performed an experiment in which alpha particles were bombarded on a thin gold foil.
Observations:
- Most alpha particles passed straight without any deflection.
- Some particles were slightly deflected.
- Very few particles bounced back.
Conclusions:
- Most of the atom is empty space.
- Positive charge is concentrated in a small region called nucleus.
- Nucleus is very small but dense.
- Electrons revolve around the nucleus.
This experiment led to the discovery of the nuclear model of atom.
OR
Bohr’s Atomic Model
Answer:
Bohr proposed a model to explain atomic structure.
- Electrons revolve around nucleus in fixed circular paths called orbits.
- Each orbit has fixed energy level.
- Electrons do not lose energy while moving in these orbits.
- Energy is absorbed or emitted when electrons jump from one orbit to another.
This model successfully explained the stability of atom and hydrogen spectrum.
Q.18. Can gravitational potential energy be negative?
Answer:
Yes, gravitational potential energy can be negative.
- Potential energy is measured with respect to a reference level.
- Usually, infinity is taken as zero potential energy.
- When an object is closer to Earth, its potential energy becomes negative.
- Negative value shows that work is required to move the object away from Earth.
Thus, gravitational potential energy is negative due to attractive force.
OR
If velocity is doubled, what happens to potential energy?
Answer:
Potential energy does not depend on velocity.
- Potential energy depends on height and mass.
- It is given by: PE = mgh
- Velocity affects kinetic energy, not potential energy.
- So, even if velocity is doubled, potential energy remains unchanged.
Q.19. Causes of diseases and vaccines
Answer:
1. Causes of diseases:
- Microorganisms like bacteria and viruses
- Poor hygiene and contaminated food/water
2. Diseases with vaccines available:
- Polio
- Tuberculosis (TB)
Vaccination helps in prevention of diseases.
OR
Types of diseases and difference
Answer:
1. Long-term (Chronic) diseases:
- Last for a long time
- Example: Diabetes
Short-term (Acute) diseases:
- Last for short time
- Example: Cold
2. Difference between diseases:
Infectious diseases:
- Spread from one person to another
- Example: Flu
Non-infectious diseases:
- Do not spread
- Example: Cancer
✍️ Credit
Prepared by: Ujjwal Matoliya