NCERT Solutions Poorvi Chapter 5 Bibha Chowdhuri — Let us learn
Book page 239 to 243 Updated on2026-09-05
Q1.
Complete the crossword puzzle by filling in the antonyms from the clues given below in the table. You may refer to the text. ACROSS — 4. core, 5. dependent, 7. extinguish, 8. terrestrial. DOWN — 1. effortless, 2. weakness, 3. neglect, 6. trivial.
Answer
Every answer is a word used in the article itself, so the text is your dictionary. Work out the length of each answer from the boxes first.
No.
Clue (find the opposite)
Letters
Answer
Where it appears in the text
4 Across
core
9
PERIPHERY
“she remained in the periphery of Indian scientific acclaim”
5 Across
dependent
10
AUTONOMOUS
“developing autonomous systems for spacecraft”
7 Across
extinguish
6
IGNITE
“the progress she helped ignite”
8 Across
terrestrial
6
COSMIC
“with every cosmic achievement”; “an eye for Cosmic Rays”
How the crossings confirm the answers: PERIPHERY crosses TENACITY at its second letter E and RECOGNITION at its seventh letter E; AUTONOMOUS supplies the O of RECOGNITION and the fifth letter O of ARDUOUS; IGNITE gives the I of PIVOTAL's second letter and RECOGNITION's seventh letter I; COSMIC gives PIVOTAL its O and RECOGNITION its ninth letter I. If even one answer were wrong, several crossings would fail — that is what makes a crossword self-checking.
Watch the shades of meaning:core and periphery are opposites of position (centre / edge); terrestrial and cosmic are opposites of place (of the Earth / of the universe); trivial and pivotal are opposites of importance (of no consequence / the point on which everything turns — from pivot, the pin a wheel spins on).
Q2.
Substitute the underlined phrase in the sentences with the suitable words from the box given below. (physicist, luminaries, pioneers, peers, barriers, persistence) 1. They are considered to be the first people to start the online markets.
Answer
They are considered to be the pioneers of the online markets.
Why: a pioneer is somebody who is first into new territory and opens it for others. The article uses the word exactly so — “the foundation was laid by early pioneers like Bibha Chowdhuri”.
Q3.
2. A scientist who studies matter, energy, light, etc.
Answer
A physicist.
Why: physics is the study of matter, energy and the forces between them, so the person who studies it is a physicist. The article calls Bibha Chowdhuri “India's first woman physicist”, and Narinder Kapany, in the earlier listening task, “an Indian physicist from Punjab”.
Do not confuse: a physicist studies physics; a physician is a doctor of medicine. One letter apart, and completely different professions.
Q4.
3. Most of my friends are my classmates and are my age.
Answer
Most of my friends are my peers.
Why: your peers are the people of the same age, rank or standing as you — hence peer group, peer pressure, and peer review, the process by which scientists' work is judged by other scientists of equal standing before it is published.
Q5.
4. We first welcomed all the famous and important people in folk song for the award ceremony.
Answer
We first welcomed all the luminaries in folk song for the award ceremony.
Why, and why the word is well chosen here: a luminary is a person who is an inspiring example in their field. The root is Latin lumen, ‘light' — the same root that runs through this whole article, where Bibha Chowdhuri is “a beam of light” and a “beacon”. The text itself uses it: “One such luminary is Dr. Ritu Karidhal Srivastava.”
Q6.
5. My brother finally succeeded in his business because of his continuous efforts and determination.
Answer
My brother finally succeeded in his business because of his persistence.
Why:persistence is exactly ‘continuing effort and determination' in one word — the glossary in your book defines it as “ability to keep doing something difficult”. The text: “Bibha's persistence eventually earned her a place at the Bose Institute.”
Q7.
6. We should remove all the things that block our way in achieving success.
Answer
We should remove all the barriers in achieving success.
Why: a barrier is anything that blocks a way. Notice that in this article the barriers are never physical — “the walls of exclusion”, a field that was “male-dominated”, a world “sceptical of her capabilities”. The verb the text uses with it is the important one: young women are inspired to “break barriers”.
Q8.
The words ‘professorship’, ‘mentorship’, and ‘leadership’ are used in the text. These words are made by adding the suffix ‘-ship’ to the words ‘professor’, ‘mentor’ and ‘leader’. Similarly, we can make words by adding -ment and -hood to certain words. Now, make words by adding suitable suffixes -ship, -ment, and -hood to the words given below. One example has been done for you. achieve + ment = achievement. 1. member 2. govern 3. partner 4. child 5. citizen 6. entertain 7. brother 8. agree
Answer
No.
Word
Suffix
New word
What the new word names
—
achieve
+ ment
achievement (example)
The result of achieving
1.
member
+ ship
membership
The state of being a member
2.
govern
+ ment
government
The act, or the body, that governs
3.
partner
+ ship
partnership
The relationship between partners
4.
child
+ hood
childhood
The period of being a child
5.
citizen
+ ship
citizenship
The status of being a citizen
6.
entertain
+ ment
entertainment
The act, or the means, of entertaining
7.
brother
+ hood
brotherhood
The condition, or a body, of brothers
8.
agree
+ ment
agreement
The act or result of agreeing
There is a pattern, and knowing it saves guessing:
-ment attaches to verbs and names the action or its result: govern → government, entertain → entertainment, agree → agreement, achieve → achievement, develop → development.
-ship attaches to nouns naming a person or role and names the position, skill or relationship: member → membership, partner → partnership, citizen → citizenship, leader → leadership, professor → professorship, friend → friendship.
-hood attaches to nouns naming a person or stage of life and names a state or a group sharing it: child → childhood, brother → brotherhood, neighbour → neighbourhood, adult → adulthood.
Every word you build with these suffixes is a noun, whatever the word you started from.
Watch the spelling: the base word does not change — agree keeps both e's in agreement, and govern loses nothing in government (though the first ‘n' is barely pronounced, which is why it is so often misspelt).
Q9.
The abbreviations—ISRO and STEM—used in the text are called acronyms because they are read or pronounced as full words. The grid given below has acronyms for the following. Circle the acronyms in the grid. 1. National Aeronautics and Space Administration 2. All India Institute of Medical Sciences 3. Ayurveda, Yoga and Naturopathy, Unani, Siddha, and Homoeopathy 4. National Institute of Pharmaceutical Education and Research 5. World Health Organization
Answer
All five acronyms are in the grid. Four run left to right along a row; one runs downwards in the first column. The letters to circle are shown in orange:
c1
c2
c3
c4
c5
c6
c7
c8
c9
r1
A
C
B
G
A
I
I
M
S
r2
Y
R
T
H
A
I
T
A
W
r3
U
S
W
H
O
C
M
T
J
r4
S
A
R
O
F
G
C
R
T
r5
H
B
N
I
P
E
R
B
I
r6
D
G
N
O
J
T
O
N
M
r7
E
F
N
A
S
A
J
E
E
No.
Full form
Acronym
Where it hides
1.
National Aeronautics and Space Administration
NASA
Row 7, columns 3–6, left to right
2.
All India Institute of Medical Sciences
AIIMS
Row 1, columns 5–9, left to right
3.
Ayurveda, Yoga and Naturopathy, Unani, Siddha, and Homoeopathy
AYUSH
Column 1, rows 1–5, downwards
4.
National Institute of Pharmaceutical Education and Research
NIPER
Row 5, columns 3–7, left to right
5.
World Health Organization
WHO
Row 3, columns 3–5, left to right
Acronym or abbreviation? An acronym is read as a word — NASA (‘nassa'), AIIMS (‘aims'), AYUSH (‘aayush'), NIPER (‘nyper'), ISRO (‘izro'), STEM, LASER, SCUBA. An initialism is spelt out letter by letter — WHO (double-you-aitch-oh), TIFR, IAU, CBSE, UPI. By this test WHO is strictly an initialism, though everyday usage lumps both together under ‘acronym'.
Search strategy for any word grid: look for the rarest letter of the word first. For AYUSH, hunt for the Y; for NIPER, for the P. There are far fewer Ys and Ps in a grid than Ns and As, so you check a handful of cells instead of dozens.
Q10.
Read the following sentence from the text and the table that follows. …, the foundation was laid by early pioneers like Bibha Chowdhuri… Here the verb is expressed in passive form. Now, complete the following news report with the passive form of verbs given in the box below. (Remember that the verb must agree with the subject.) Box: discover, test, measure, publish, record, take. — Last year, significant advancements in medical science 1. __________ in leading medical journals when a new vaccine for malaria 2. __________. The vaccine 3. __________ through several clinical trials and results 4. _________ in those journals. During the trials, blood samples 5. __________ regularly from participants to monitor their immune response. The amount of antibodies produced 6. __________ carefully to assess the effectiveness of the vaccine.
Answer
No.
Subject
Number
Passive form
1.
significant advancements
plural
were published
2.
a new vaccine
singular
was discovered
3.
The vaccine
singular
was tested
4.
results
plural
were recorded
5.
blood samples
plural
were taken
6.
The amount of antibodies produced
singular (‘the amount')
was measured
The completed report: Last year, significant advancements in medical science were published in leading medical journals when a new vaccine for malaria was discovered. The vaccine was tested through several clinical trials and results were recorded in those journals. During the trials, blood samples were taken regularly from participants to monitor their immune response. The amount of antibodies produced was measured carefully to assess the effectiveness of the vaccine.
Two rules are being tested at once.
Form: the passive is be + past participle. Here the time is past (‘Last year'), so it is was/were + participle.
Agreement: ‘was' or ‘were' is decided by the subject, not by the doer. Trap number 6 is the interesting one: the subject is “The amount… ” — amount is singular, so was measured, even though ‘antibodies' stands right beside the verb.
Why science writing loves the passive: in a scientific report, who did the work is usually irrelevant and often unknown to the reader — what matters is what was done to the sample. ‘Blood samples were taken regularly' keeps the attention on the method, which is why journals are written this way and why this exercise sits in a chapter about a physicist.
Q11.
Read the following report of an experiment. Rewrite the report using passive verbs wherever necessary. I conducted an experiment to investigate the effects of light on plant growth. I placed various plants under different light conditions and measured their growth over several weeks. I recorded data daily to track the height of each plant. At the end of the experiment, I analysed the results and found that plants exposed to natural light grew significantly taller than those under artificial light. I concluded that sunlight plays a crucial role in plant development. I presented my findings to the class, highlighting the importance of light in enhancing photosynthesis and overall plant health. You may begin like this. An experiment was conducted…
Answer
The report in the passive voice
An experiment was conducted to investigate the effects of light on plant growth. Various plants were placed under different light conditions and their growth was measured over several weeks. Data was recorded daily to track the height of each plant. At the end of the experiment, the results were analysed and it was found that plants exposed to natural light grew significantly taller than those under artificial light. It was concluded that sunlight plays a crucial role in plant development. The findings were presented to the class, highlighting the importance of light in enhancing photosynthesis and overall plant health.
Active
Passive
I conducted an experiment
An experiment was conducted
I placed various plants
Various plants were placed
…and measured their growth
…and their growth was measured
I recorded data daily
Data was recorded daily
I analysed the results
The results were analysed
I found that…
It was found that…
I concluded that…
It was concluded that…
I presented my findings
The findings were presented
The trap in this exercise is the words ‘wherever necessary'. One clause must stay active: “plants exposed to natural light grew significantly taller”. Grow here is intransitive — nobody grew the plants, the plants grew — and a verb with no object cannot be made passive. Rewriting it as ‘were grown taller' would change the meaning entirely. Check every verb for an object before you convert it.
How to convert, in three steps: (1) make the old object the new subject; (2) put the verb into be + past participle, keeping the tense; (3) drop the doer, or add it with by if it matters. Here the doer is ‘I' throughout, and removing it is the whole point — a scientific report is meant to describe the method, not the person.
Q12.
Read the instructions given in the box on landing of Chandrayaan. Complete the passage by choosing the correct answer from the options given. (Instructions: • Launch the spacecraft towards the Moon from Earth. • Position the spacecraft to enter the Moon’s orbit. • Adjust the spacecraft’s path for landing. • Slow down the spacecraft as it nears the Moon’s surface. • Release the rover to explore the surface and collect valuable data.) Chandrayaan’s landing mission involves several key steps. First, the spacecraft 1.________ towards the Moon from the Earth. Then, it 2. ________ to enter the Moon’s orbit. After reaching the Moon’s orbit, the spacecraft’s path 3. ________ for landing. Next, the spacecraft 4. ________ as it nears the Moon’s surface. Finally, the rover 5.________ to explore the surface and collect valuable data. (i) A. launched B. were launched C. was launched D. is launched (ii) A. position B. was positioned C. is positioned D. has positioned (iii) A. adjusted B. was adjusted C. is adjusted D. were adjusted (iv) A. slowed down B. was slowed down C. is slowed down D. were slowed down (v) A. is released B. has released C. were released D. was released
Answer
No.
Answer
Subject
Why
(i)
D. is launched
the spacecraft (singular)
Present simple passive
(ii)
C. is positioned
it — the spacecraft (singular)
Present simple passive
(iii)
C. is adjusted
the spacecraft's path (singular)
Present simple passive
(iv)
C. is slowed down
the spacecraft (singular)
Present simple passive
(v)
A. is released
the rover (singular)
Present simple passive
The completed passage: Chandrayaan's landing mission involves several key steps. First, the spacecraft is launched towards the Moon from the Earth. Then, it is positioned to enter the Moon's orbit. After reaching the Moon's orbit, the spacecraft's path is adjusted for landing. Next, the spacecraft is slowed down as it nears the Moon's surface. Finally, the rover is released to explore the surface and collect valuable data.
Two decisions settle all five blanks.
Tense. The opening sentence is present — “Chandrayaan's landing mission involves several key steps” — and the box gives general instructions, not the history of one flight. So the whole passage stays in the present, and every past form (was launched, was positioned…) is out.
Number. Each subject is singular — the spacecraft, the path, the rover — so it is is, never were. That removes B in (i), and D in (iii) and (iv), at once.
Options A in (i), (ii), (iii) and (iv) are active or bare forms and cannot follow a subject that receives the action; B in (v), ‘has released', would mean the rover released something, which reverses the meaning.
Why the passive is right here at all: the doer — ISRO's flight team, and the onboard software — is obvious and not the point. What the passage is describing is the sequence of things done to the spacecraft. That is the second of the three conditions listed on page 242: the passive is used when the doer of the action is obvious.