Science syllabus

Question 1

Amla

Answer 1

Acidic

Question 2

Acid-base indicator

Answer 2

Substances that show different colours in acidic and basic solutions

Question 3

Lichen

Answer 3

Association of algae and fungi; grows on rocks/trees in clean, rainy regions

Question 4

Acidic substances

Answer 4

Taste sour; turn blue litmus red

Question 5

Basic substances

Answer 5

Taste bitter; turn red litmus blue

Question 6

Neutral

Answer 6

Neither acidic nor basic; no litmus colour change

Question 7

Lemon juice

Answer 7

Contains citric acid

Question 8

Amla (composition)

Answer 8

Contains ascorbic acid and citric acid

Question 9

Unripe mangoes

Answer 9

Contain tartaric acid

Question 10

Tomatoes

Answer 10

Contain citric and oxalic acids

Question 11

Curd

Answer 11

Contains lactic acid

Question 12

Tamarind

Answer 12

Contains tartaric acid

Question 13

Vinegar

Answer 13

Contains acetic acid

Question 14

Turmeric

Answer 14

Contains curcumin

Question 15

Preparation of rose extract

Answer 15

Crush petals → add hot water → filter; filtrate is the extract

Question 16

Other natural indicators

Answer 16

Beetroot, purple cabbage, turmeric, jamun, red hibiscus

Question 17

Hydrangea colour change

Answer 17

Blue in acidic soil; red in basic soil

Question 18

Turmeric paper indicator

Answer 18

Detects only bases (not acids or neutrals)

Question 19

Turmeric (description)

Answer 19

A golden spice from the ginger family; used in Indian households and remedies

Question 20

Olfactory indicators

Answer 20

Substances whose smell changes in acids or bases

Question 21

Father of Modern Indian Chemistry

Answer 21

Acharya Prafulla Chandra Ray

Question 22

Neutralisation

Answer 22

Acid + base → salt + water + heat

Question 23

Why soil becomes acidic

Answer 23

Excessive use of chemical fertilisers

Question 24

Treatment of acidic soil

Answer 24

Add lime (a base)

Question 25

Treatment of basic soil

Answer 25

Add organic matter

Question 26

Why plants grow poorly even in neutral soil

Answer 26

Nutrient deficiency

Question 27

Positive terminal

Answer 27

Small protruding cap

Question 28

Negative terminal

Answer 28

Flat metal disk

Question 29

Utility of electric cell

Answer 29

Portable power source

Question 30

Battery

Answer 30

Combination of two or more cells

Question 31

Connecting multiple cells

Answer 31

Provides more energy for longer time

Question 32

Why phone battery is called “battery” even with one cell

Answer 32

Historical naming; structure has one cell but retains the term

Question 33

Filament

Answer 33

Thin wire in a bulb that glows when heated

Question 34

LED

Answer 34

Light Emitting Diode

Question 35

Electric circuit

Answer 35

A path for current between terminals

Question 36

Bulb vs LED

Answer 36

Bulb has filament; LED does not; both have two terminals

Question 37

Current flow in bulb

Answer 37

Flows when both terminals are connected; direction doesn’t affect glowing

Question 38

Closed circuit

Answer 38

Complete path; circuit is ON

Question 39

Open circuit

Answer 39

Incomplete path; circuit is OFF

Question 40

Switch placement

Answer 40

Can be placed anywhere in the circuit

Question 41

Switch

Answer 41

Device that completes or breaks a circuit

Question 42

LED symbol (triangle + arrows)

Answer 42

Triangle shows current direction; arrows show light emission

Question 43

Circuit diagram

Answer 43

Symbol-based representation of a circuit

Question 44

Why copper is used

Answer 44

Abundant and low-cost conductor

Question 45

AC

Answer 45

Alternating Current; from wall sockets; runs large appliances

Question 46

DC

Answer 46

Direct Current; from batteries; powers small devices