The following 20 Multiple Choice Questions (MCQ) are based on
Chapter 1: Exploration: Entering the World of Secondary Science from the NCERT Class 9
Science textbook Exploration. Each question has four options - select the
best answer and click to check.
Instructions: Read each question carefully. Choose the most
appropriate option from (a), (b), (c), or (d). Click
Show Answer to reveal the correct answer with explanation.
Multiple Choice Questions
1Why do scientists use models?
(a) To copy every detail of a system
(b) To simplify complex systems for a specific question
(c) To avoid making measurements
(d) To prove every theory is final
(b) is correct
A scientific model keeps the features relevant to a question and deliberately leaves out less important details.
2In a simple model of whether a cricket ball will cross the boundary, which detail is most relevant?
(a) Colour of the ball
(b) Brand of the bat
(c) Speed and direction of the ball
(d) Amount of grass beside the pitch
(c) is correct
The ball's speed and direction strongly affect its path; colour and brand do not answer the question.
3Why may air resistance be ignored in a simple model of a falling object?
(a) Air does not exist
(b) Gravity stops acting in air
(c) To isolate the basic effect of gravity
(d) To make the object fall upward
(c) is correct
Ignoring a smaller effect can make the main relationship easier to understand before the model is refined.
4What does the magnifying glass in the textbook's page design symbolise?
(a) Careful observation
(b) Fast calculation
(c) Laboratory safety
(d) A final conclusion
(a) is correct
It represents noticing patterns and details that might otherwise be missed.
5What does the compass symbolise in scientific exploration?
(a) Travelling without a purpose
(b) Direction through suitable questions and models
(c) Measuring only geographical distance
(d) Replacing evidence with opinion
(b) is correct
Exploration needs direction: appropriate models, useful questions and awareness of a model's limits.
6Why does science use agreed symbols and standard units?
(a) To make results difficult to read
(b) To restrict science to one country
(c) To communicate and compare results unambiguously
(d) To eliminate the need for evidence
(c) is correct
Shared terms, symbols and units let people everywhere interpret and compare measurements consistently.
7Which pair correctly matches a physical quantity with the symbol given in the chapter?
(a) Mass - m
(b) Velocity - F
(c) Force - I
(d) Electric current - v
(a) is correct
The chapter uses m for mass, v for velocity, F for force and I for electric current.
8In science, an equation is best viewed as:
(a) A sentence to memorise without context
(b) A compact statement relating quantities
(c) A substitute for observation
(d) An untested opinion
(b) is correct
Equations express relationships among quantities and help us reason about a situation.
9What is the best first step before using a mathematical equation in science?
(a) Insert random numbers
(b) Memorise all units
(c) Understand the situation and identify relevant quantities
(d) Ignore the meaning of the symbols
(c) is correct
Scientific calculation begins with understanding the situation and deciding which quantities matter.
10What mainly caused the aircraft fuel error described in the chapter?
(a) A mix-up between pounds and kilograms
(b) A faulty compass
(c) A wrong weather forecast
(d) A damaged fuel tank
(a) is correct
The crew used a fuel density involving pounds per litre instead of kilograms per litre, causing a major shortage.
11Which statement correctly distinguishes a scientific law from a theory?
(a) A law is a guess, while a theory is a fact
(b) A law describes a regular pattern; a theory explains why patterns occur
(c) A theory can never change
(d) A law needs no evidence
(b) is correct
Laws describe observed regularities, while theories provide evidence-based explanations.
12In science, the word 'theory' refers to:
(a) An unsupported guess
(b) An explanation supported by careful testing
(c) A personal belief
(d) A rule that can never be questioned
(b) is correct
A scientific theory is evidence-based and critically examined, though it remains open to improvement.
13What should scientists do when a prediction does not match observation?
(a) Change the observation
(b) Ignore the mismatch
(c) Re-examine assumptions, models and measurements
(d) Keep the theory unchanged forever
(c) is correct
A mismatch is useful evidence that can reveal limits or errors and guide better explanations.
14Which question makes a rain prediction more scientifically testable?
(a) Do dark clouds look frightening?
(b) Is rain good or bad?
(c) What are today's humidity, temperature and wind conditions?
(d) Should everyone carry an umbrella?
(c) is correct
Measurable conditions and past patterns turn a vague claim into a testable prediction.
15Why do long-range weather forecasts have greater uncertainty?
(a) Weather has no measurable factors
(b) Small differences in changing conditions can grow over time
(c) Models work only at night
(d) Humidity never changes
(b) is correct
Weather depends on many interacting variables, and small initial differences can lead to different outcomes later.
16Which statement about scientific theories is correct?
(a) Every successful theory is final
(b) Theories are rejected by opinion
(c) Theories have limits and remain open to evidence
(d) New measurements weaken science
(c) is correct
Openness to correction by new evidence is a strength of science.
17What is a major value of making rough estimates?
(a) They always replace exact measurement
(b) They help detect unreasonable answers
(c) They remove the need for units
(d) They guarantee a precise result
(b) is correct
Estimation builds intuition and quickly reveals results that are implausibly large or small.
18Using about 20,000 breaths per day and 0.5 L per breath gives an estimated daily air intake of:
(a) 100 L
(b) 1,000 L
(c) 10,000 L
(d) 100,000 L
(c) is correct
20,000 x 0.5 L = 10,000 L, an approximate value used in the chapter.
19Why are physics, chemistry, biology and earth science divided into branches?
(a) Nature itself has strict boundaries
(b) To organise knowledge conveniently
(c) Because the branches never interact
(d) To prevent interdisciplinary work
(b) is correct
The divisions help organise study; real systems and problems often connect several branches.
20Which combination helps explain how a protective mask works?
(a) Only biology
(b) Only mathematics
(c) Physics, chemistry, biology and mathematics
(d) Only earth science
(c) is correct
Particle motion, polymer properties, virus behaviour and airflow modelling draw on multiple disciplines.
What is covered in CBSE Class 9 Science Chapter 1 Exploration: Entering the World of Secondary Science?
This chapter covers all key topics from Exploration: Entering the World of Secondary Science as per CBSE 2026-27 syllabus.
Is this MCQ Test useful for CBSE board exams?
Yes, designed for CBSE Class 9 board exam preparation covering the complete syllabus.
Are these CBSE Class 9 Science MCQ Test updated for 2026-27?
Yes, all content at eBookPublisher is updated as per the latest 2026-27 CBSE syllabus.
How many chapters are in CBSE Class 9 Science?
All chapters of CBSE Class 9 Science are covered at eBookPublisher with free MCQ Test for each chapter.
Can I study Exploration: Entering the World of Secondary Science online for free?
Yes, complete MCQ Test for Exploration: Entering the World of Secondary Science is available free at eBookPublisher. Study online directly — no download needed.
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