Chemical Effects of Electric Current pe poori practice: kaunse liquids electricity conduct karte hain (tester, LED aur magnetic compass se check), tap water aur distilled water ka farak, current se solution mein chemical change (gas bubbles, metal ki layer, colour change), water ka electrolysis, electroplating ka setup aur uske uses (chromium, tin, zinc, gold-silver), aur safety. Pehle chhota recap (saare naye words wahin samjhaaye hain), phir MCQs, fill in the blanks, true/false, short aur long answer, HOTS, aur end mein answer key, sab ke solutions Hinglish mein step by step. Isse apne current chapter Ch 4: Electricity: Magnetic and Heating Effects ke saath padhiye (yeh chapter is unit ka kuch part padhata hai). β‘
π§ Concept Recap: Pehle Yeh Yaad Kar Lo
π Current chapter: Ch 4: Electricity: Magnetic and Heating Effects (yeh chapter is unit ka kuch part padhata hai: current, circuit aur current ke effects). Is chapter ka hub page jald aa raha hai; tab tak Class 8 Science (saare chapters) dekho.
π Pehle yeh words samjho (aage yahi words use honge):
- Electric current = wire mein electricity ka flow. Current tabhi flow karta hai jab circuit poora (closed) ho: battery β wire β bulb β wire β wapas battery.
- Battery / cell = electricity dene wala source. Iske do ends hote hain: positive terminal (+) aur negative terminal (β).
- Conductor = jisme se current aasaani se flow kare (copper, iron, aluminium). Insulator (poor conductor) = jisme se current flow na kare ya bahut kam kare (plastic, rubber, dry wood).
- Solution = kisi cheez ko liquid mein dissolve karke bana mixture, jaise salt + water = salt solution. Distilled water = boil karke bhaap (steam) ko thanda karke bana bilkul pure water, jisme koi salt ghula nahi hota.
- Acid, base, salt = teen tarah ki cheezein jinke solutions mein current flow karta hai. Acid (khatta): lemon juice, vinegar. Base: soap solution. Salt: common salt (namak wala salt), copper sulphate.
- Tester = liquid conduct karta hai ya nahi, yeh check karne ka chhota circuit: battery + bulb + do wires jinke free ends liquid mein dubaate hain.
- LED (Light Emitting Diode) = chhota bulb jo bahut weak current pe bhi glow karta hai. Iski lambi leg positive terminal se aur chhoti leg negative se connect hoti hai; ulta connect karo to glow nahi karega.
- Magnetic compass = jisme ek chhoti magnetic needle hoti hai. Paas ke wire mein current flow kare to needle hil jaati hai (deflect hoti hai). Yeh current ka magnetic effect hai; weak current bhi pakad leta hai.
- Electrode = solution mein dubaayi metal plate ya carbon rod jisse current solution mein jaata ya bahar aata hai.
- Chemical change = jisme nayi cheez banti hai (jaise gas, metal ki layer, ya colour badalna). Current flow karne se solution mein chemical change hona current ka chemical effect hai.
- Electrolysis = current flow karke kisi solution ko todna (jaise water se hydrogen aur oxygen gas banana).
- Electroplating = electricity ki madad se ek metal ki thin layer doosre metal ki cheez pe chadhaana.
- Corrosion aur rust = air aur moisture se metal ka dheere-dheere kharaab hona. Iron pe brown layer = rust.
- Reactive = jo aasaani se doosri cheezon se chemical change karta hai. Tin, iron se kam reactive hai.
- Filament = bulb ke andar ka bahut thin wire jo current flow hone pe garam hokar glow karta (chamakta) hai. Ghar ke purane yellow bulb ke andar jo chamakta hua thin wire dikhta hai, wahi filament hai. Current weak ho to filament itna garam nahi hota ki glow kare.
- Concentration = solution mein kitni cheez dissolve hai, liquid ki utni hi quantity mein. Jaise ek glass water mein 1 spoon sugar = kam meetha (low concentration), 3 spoon sugar = zyada meetha (high concentration). βConcentration same rehta haiβ matlab solution na zyada strong hua, na zyada weak.
- Mass = kisi cheez mein kitna matter (material) hai; weighing machine pe hum yahi measure karte hain. Unit: g (gram) aur kg (1 kg = 1000 g). Jaise ek chhoti iron key ka mass lagbhag 20 g.
- Volume = koi cheez kitni jagah (space) leti hai. Liquid ya gas ka volume mL (millilitre) mein measure karte hain (1 litre = 1000 mL). Jaise ek chhoti spoon mein lagbhag 5 mL water aata hai, ek water bottle mein 1000 mL.
- Beaker = glass ka chauda, seedha container (bade glass jaisa) jisme lab mein liquid rakhte hain. Test tube = glass ki thin, lambi tube jo ek end pe band (closed) hoti hai, jaise ek chhoti thin glass bottle; gas ya thoda liquid collect karne ke liye.
- Glowing splinter = wood ki thin stick (jaise matchstick ya agarbatti ki stick) jise jala kar phir flame bujha dete hain, to sirf uska end laal glow karta hai, flame nahi hoti. Oxygen mein yeh phir se flame ke saath jal uthti hai; isse oxygen pehchaante hain.
1. Kaunse liquids conduct karte hain?
| Liquid | Tester mein kya hota hai | Reason |
|---|---|---|
| Lemon juice, vinegar | Bulb/LED glow karta hai β | Acid ke solution |
| Salt water, tap water | Glow β (tap water mein LED/compass se pakka pata chalta hai) | Ghule hue salts |
| Distilled water | Glow nahi β (poor conductor) | Koi salt ghula nahi |
| Sugar solution, vegetable oil | Glow nahi β | Acid, base ya salt nahi |
Dhyaan: bulb na jale to iska matlab hamesha βnon-conductorβ nahi. Ho sakta hai current itna weak ho ki bulb ka filament (bulb ke andar ka thin wire, recap dekho) garam hokar glow na kare. Tab LED ya magnetic compass wala tester use karo.
2. Current se chemical change ke signs
- Gas bubbles electrodes pe (jaise water ke electrolysis mein).
- Metal ki layer kisi electrode pe jamna (jaise electroplating mein copper).
- Colour change solution ya kisi cheez ka (jaise potato mein positive wire ke paas greenish-blue spot).
Water ka electrolysis: thoda acid mila water lo, do carbon electrodes battery se connect karo. Negative electrode pe hydrogen aur positive electrode pe oxygen ke bubbles bante hain. Hydrogen ka volume oxygen se lagbhag 2 times hota hai (water mein hydrogen ke 2 parts aur oxygen ka 1 part hai). Test: hydrogen ke paas jalti matchstick β βpopβ sound; oxygen mein glowing splinter (bujhi hui wood ki stick jiska end laal glow kar raha ho, recap dekho) phir se jal uthti hai.
3. Electroplating (copper ka example)
| Part | Kya hota hai |
|---|---|
| Copper sulphate solution (blue) | Current ko flow karne deta hai; iska concentration (solution kitna strong hai, recap dekho) lagbhag same rehta hai |
| Copper plate, positive terminal se | Iska copper solution mein ghulta hai, plate dheere-dheere thin hoti hai |
| Object (key), negative terminal se | Is par copper ki thin layer jamti hai |
Rule yaad rakho: jis cheez pe coating chahiye, use negative terminal se connect karo; coating wala metal positive terminal se.
| Use | Kaunsa metal kis par | Kyun |
|---|---|---|
| Taps, cycle handle, car parts | Chromium, cheaper metal par | Shiny, corrosion nahi hota, scratch nahi padta; par chromium mehenga hai, isliye sirf layer |
| Food ke tin cans | Tin, iron par | Tin iron se kam reactive; food iron ke contact mein nahi aata, kharaab nahi hota |
| Bridges, vehicles ke iron parts | Zinc, iron par | Rust aur corrosion se bachaav |
| Jewellery | Gold ya silver, sasti metal par | Kam price mein gold/silver jaisa look |
β οΈ Safety: experiments sirf chhoti battery (cells) se karo; ghar ke switch board (mains), generator ya inverter se kabhi nahi. Gile haathon se switch mat chhoo: tap water conductor hai. Electroplating factory ke used solutions ko seedha drain ya river mein daalna pollution karta hai; inhe rules ke hisaab se treat karke hi dispose karna chahiye.
β π charumam.com
π Section A: 10 MCQs
Har sawaal ke 4 options mein se ek sahi chuno. Pehle khud socho, phir βSolution dekhoβ kholo.
Q1. Inmein se kaunsa liquid electricity ka poor conductor hai?
Solution (step by step) dekho
Sahi answer: (b) Distilled water
Step 1: liquid tab conduct karta hai jab usme acid, base ya salt ghula ho.
Step 2: lemon juice aur vinegar acid hain, salt water mein salt hai. Distilled water mein kuch nahi ghula, isliye woh poor conductor hai.
Q2. Tester ke ends liquid mein daale par bulb nahi jala. Pakka check karne ke liye kya karoge?
Solution (step by step) dekho
Sahi answer: (a) Bulb ki jagah LED ya magnetic compass wala tester use karoge
Step 1: weak current pe bulb ka filament glow nahi karta.
Step 2: LED bahut weak current pe bhi glow karta hai, aur compass needle weak current pe bhi deflect hoti hai. To (a) sahi hai. Lamba wire ya distilled water current aur kam karenge; battery hataane se current hi nahi.
Q3. Electroplating mein jis cheez pe coating chadhani ho, use kis terminal se connect karte hain?
Solution (step by step) dekho
Sahi answer: (b) Negative terminal
Coating wala metal (jaise copper) positive terminal se nikal kar solution se hote hue negative terminal wale electrode pe jamta hai. Isliye object ko negative terminal se connect karte hain.
Q4. Copper sulphate solution ka colour kaisa hota hai?
Solution (step by step) dekho
Sahi answer: (b) Blue
Copper sulphate solution blue colour ka hota hai. Isi liye electroplating setup mein beaker ka solution blue dikhta hai.
Q5. Food store karne wale cans mein iron par kis metal ki layer hoti hai?
Solution (step by step) dekho
Sahi answer: (c) Tin
Tin, kyunki tin iron se kam reactive hai. Food seedha iron ke contact mein nahi aata, isliye kharaab nahi hota.
Q6. Tap water electricity conduct karta hai kyunki:
Solution (step by step) dekho
Sahi answer: (b) Usme thode salts (minerals) ghule hote hain
Tap water mein natural salts ghule hote hain; yahi current ko flow karne dete hain. Inhe hata do (distilled water) to conduction lagbhag khatam.
Q7. Thoda acid mile water ke electrolysis mein negative terminal wale electrode pe kaunsi gas banti hai?
Solution (step by step) dekho
Sahi answer: (b) Hydrogen
Negative electrode pe hydrogen aur positive electrode pe oxygen. Hydrogen ka volume lagbhag 2 times hota hai.
Q8. Bridges aur vehicles ke iron parts par zinc ki layer kyun chadhaate hain?
Solution (step by step) dekho
Sahi answer: (b) Rust aur corrosion se bachaane ke liye
Zinc ki layer iron ko air aur moisture se door rakhti hai, isliye rust aur corrosion nahi hota.
Q9. Copper electroplating ke dauran positive terminal wali copper plate ka kya hota hai?
Solution (step by step) dekho
Sahi answer: (b) Dheere-dheere thin hoti jaati hai
Positive terminal wali plate ka copper solution mein ghulta hai, isliye plate thin hoti hai. Utna hi copper negative electrode wali cheez pe jamta hai, isliye solution ka concentration lagbhag same rehta hai.
Q10. LED ko tester mein lagaate waqt uski lambi leg kis terminal se connect hoti hai?
Solution (step by step) dekho
Sahi answer: (b) Positive
LED ki lambi leg positive terminal se aur chhoti leg negative se. Ulta connect karo to LED glow nahi karega, chaahe current flow ho sake.
β π charumam.com
βοΈ Section B: Fill in the Blanks
Blank (_____) mein sahi word ya number bharo.
Q1. Current flow karne se solution mein chemical change hona current ka _____ effect hai.
Answer aur reason
Answer: chemical
Nayi cheez banna (gas, metal layer, colour change) chemical change hai, isliye ise current ka chemical effect kehte hain.
Q2. Solution mein dubaayi metal plates ya carbon rods ko _____ kehte hain.
Answer aur reason
Answer: electrodes
Electrode se current solution mein jaata ya bahar aata hai.
Q3. Electricity se ek metal ki thin layer doosre metal par chadhaana _____ kehlaata hai.
Answer aur reason
Answer: electroplating
Electro (electricity) + plating (layer chadhaana) = electroplating.
Q4. Taps aur cycle handles par shiny, scratch-resistant layer _____ ki hoti hai.
Answer aur reason
Answer: chromium
Chromium shiny hai, corrode nahi hota, par mehenga hai, isliye sirf thin layer chadhaate hain.
Q5. Distilled water mein thoda common _____ dissolve kiya jaaye to woh conduct karne lagta hai.
Answer aur reason
Answer: salt
Salt ghulne se solution conductor ban jaata hai.
Q6. Paas ke wire mein current flow kare to magnetic compass ki needle _____ hoti hai.
Answer aur reason
Answer: deflect
Current ka magnetic effect needle ko apni position se hila deta hai (deflect).
Q7. Potato mein battery se connected do wires ghusaao to _____ terminal wale wire ke paas greenish-blue spot banta hai.
Answer aur reason
Answer: positive
Yeh chemical effect ka sign hai; isse battery ka positive terminal pehchaan sakte hain.
Q8. Water ke electrolysis mein hydrogen ka volume oxygen se lagbhag _____ times hota hai.
Answer aur reason
Answer: 2
Water mein hydrogen ke 2 parts aur oxygen ka 1 part hota hai, isliye hydrogen lagbhag 2 times.
β π charumam.com
β β Section C: True / False
Batao statement sahi (True) hai ya galat (False). False ho to use sahi karke likho.
Q1. Har liquid electricity conduct karta hai.
Answer aur reason
β False
False. Distilled water, sugar solution aur vegetable oil current conduct nahi karte (ya bahut kam). Sirf acids, bases aur salts ke solutions achhe conductors hain.
Q2. Gile haathon se electric switch chhoona khatarnak hai.
Answer aur reason
β True
True. Tap water mein salts hote hain, isliye woh conductor hai; current gile haath se body mein ja sakta hai.
Q3. Electroplating mein object ko positive terminal se connect kiya jaata hai.
Answer aur reason
β False
False. Object negative terminal se; coating wala metal positive terminal se.
Q4. Tin, iron se kam reactive metal hai.
Answer aur reason
β True
True. Isi liye food cans mein iron par tin ki layer chadhaate hain.
Q5. LED tester bahut weak current pe bhi glow kar sakta hai.
Answer aur reason
β True
True. LED ko glow karne ke liye bulb se kahin kam current chahiye.
Q6. Distilled water electricity ka achha conductor hai.
Answer aur reason
β False
False. Distilled water mein koi salt nahi ghula, isliye woh poor conductor hai.
Q7. Electroplating factory ka used solution seedha river mein daalna safe hai.
Answer aur reason
β False
False. Usme metals aur chemicals hote hain jo water ko pollute karte hain; ise treat karke hi dispose karna chahiye.
Q8. Current flow hone pe electrodes par gas bubbles banna chemical change ka sign hai.
Answer aur reason
β True
True. Bubbles nayi gas (jaise hydrogen, oxygen) ke bane hain, yaani nayi cheez bani.
β π charumam.com
π’ Section D: Short Answer Questions
2 se 3 marks wale sawaal. Har step likhne ki habit daalo.
Q1. Ghar ki cheezon se ek tester kaise banaoge? Usse kaise pata chalega ki liquid conduct karta hai?
Step-by-step solution
Step 1 (cheezein): ek battery, ek chhota bulb (ya LED), aur teen wires.
Step 2 (circuit): battery ka ek terminal bulb se connect karo. Bulb ka doosra end ek wire se, aur battery ka doosra terminal doosre wire se. Dono wires ke free ends khule rakho.
Step 3 (pehle check): dono free ends ko aapas mein chhoao: bulb jale to tester theek hai.
Step 4 (test): free ends ko liquid mein dubaao (ek doosre ko chhue bina). Bulb jale to liquid conductor β ; na jale to LED ya compass se dobara check karo.
Q2. Tap water conduct karta hai par distilled water nahi. Kyun? Distilled water ko conductor kaise banaoge?
Step-by-step solution
Step 1: tap water mein natural salts (minerals) ghule hote hain, jo current flow karne dete hain.
Step 2: distilled water mein koi salt nahi, isliye woh poor conductor.
Step 3: distilled water mein thoda common salt (ya lemon juice) milao: ab woh conduct karega.
Q3. Current se solution mein chemical change hua hai, iske teen observable signs likho (har ek ka example).
Step-by-step solution
1. Gas bubbles electrodes par: acid mile water mein carbon electrodes par hydrogen aur oxygen.
2. Metal ki layer jamna: copper sulphate solution mein negative electrode wali key par copper.
3. Colour change: potato mein positive wire ke paas greenish-blue spot.
Q4. Electroplating ke teen uses likho, har ek ka reason ke saath.
Step-by-step solution
1. Chromium taps aur cycle handles par: shiny, corrode nahi hota, scratch-resistant; mehenga hai, isliye sirf layer.
2. Tin food cans mein iron par: tin kam reactive, food kharaab nahi hota.
3. Zinc bridges aur vehicles ke iron par: rust aur corrosion se bachaav. (Gold/silver jewellery bhi sahi example hai.)
Q5. Tester ka bulb kisi liquid mein nahi jala. Kya iska matlab hamesha yahi hai ki liquid non-conductor hai? Do reasons do.
Step-by-step solution
Nahi. (1) Current itna weak ho sakta hai ki bulb ka filament glow na kare; LED ya compass se check karna chahiye. (2) Circuit mein koi loose connection ho sakta hai ya battery weak ho sakti hai; isliye pehle free ends ko aapas mein chhoa kar tester check karte hain.
Q6. Copper electroplating se pehle positive terminal wali copper plate ka mass 50 g tha; baad mein 47.6 g reh gaya. Iron key ka mass pehle 20 g tha. Agar plate se nikla saara copper key par jama ho, to key ka naya mass kya hoga?
Step-by-step solution
Step 1 (plate ne kitna copper khoya): 50 β 47.6 = 2.4 g.
Step 2: utna hi copper key par jama (solution ka concentration same raha).
Step 3: key ka naya mass = 20 + 2.4 = 22.4 g.
β π charumam.com
π Section E: Long Answer Questions
4 se 5 marks wale sawaal. Solution mein har step ka reason bhi likha hai.
Q1. Copper electroplating ka activity samjhao: kya chahiye, kaise connect karoge, dono electrodes par kya hoga, aur solution ka concentration same kyun rehta hai.
Step-by-step solution
Step 1 (cheezein): beaker mein copper sulphate solution (blue), ek copper plate, ek saaf iron key (sandpaper se ragad kar), battery, wires.
Step 2 (connect karna): copper plate ko battery ke positive terminal se, key ko negative terminal se connect karo. Dono ko solution mein dubaao, aapas mein chhue bina.
Step 3 (current flow karo, 15β20 minute): key par copper ki brownish-red layer jamti hai; copper plate dheere-dheere thin hoti hai.
Step 4 (concentration same kyun): jitna copper solution se nikal kar key par jamta hai, utna hi copper positive plate se solution mein aa jaata hai. Isliye solution mein copper lagbhag utna hi rehta hai.
Step 5 (electrodes badal do to?): key positive se connect hogi to us par coating nahi jamegi.
Q2. Thoda acid mile water ka electrolysis: setup, observations, gases ki pehchaan, aur agar negative electrode par 30 mL gas bani to positive electrode par kitni gas banegi?
Step-by-step solution
Step 1 (setup): beaker mein water + thoda acid; do carbon electrodes battery se connected; har electrode ke upar ek water se bhari ulti test tube.
Step 2 (observation): dono electrodes par bubbles; gas test tubes mein jama hoti hai aur water ko neeche dhakelti hai.
Step 3 (pehchaan): negative electrode wali gas = hydrogen (jalti matchstick se βpopβ sound). Positive electrode wali = oxygen (glowing splinter phir jal uthti hai).
Step 4 (volume): hydrogen ka volume oxygen ka lagbhag 2 times. To oxygen = 30 Γ· 2 = 15 mL. Total gas = 30 + 15 = 45 mL.
Q3. Riya ne tester se 6 liquids check kiye: lemon juice, vinegar, tap water, distilled water, sugar solution, vegetable oil. Kaunse conduct karenge aur kaunse nahi? Table banao aur har ek ka reason do. Ek observation weak kyun ho sakta hai?
Step-by-step solution
Conduct karenge: lemon juice (acid), vinegar (acid), tap water (ghule salts).
Nahi karenge (ya bahut kam): distilled water (koi salt nahi), sugar solution (sugar acid/base/salt nahi), vegetable oil (insulator).
Weak observation: tap water mein salts kam hote hain, isliye bulb dim ya bilkul na jale; LED ya compass se conduction saaf dikhega.
Q4. Electricity aur liquids ke saath kaam karte waqt kaunsi safety rakhni chahiye? Electroplating ke environment par asar aur uska solution bhi likho.
Step-by-step solution
Step 1 (experiments): sirf chhoti battery se; mains switch board, generator ya inverter se kabhi nahi, kyunki unka current jaan le sakta hai.
Step 2 (ghar mein): gile haathon se switch ya plug mat chhoo; bathroom mein electric cheezein dhyaan se; tap water conductor hai.
Step 3 (environment): electroplating factories ke used solutions mein metals aur chemicals hote hain; seedha drain ya river mein daalne se water pollute hota hai aur fish/plants ko nuksaan.
Step 4 (solution): waste solution ko treat karke, rules ke hisaab se dispose karna; metals ko recover karke dobara use karna.
β π charumam.com
𧩠Section F: HOTS (Soch Wale Sawaal)
HOTS matlab Higher Order Thinking Skills: aise sawaal jinme formula se aage thoda mind lagana padta hai.
Q1. Ek liquid mein tester daala: paas rakhi compass ki needle deflect hui, par bulb nahi jala. Iska kya matlab hai?
Soch aur solution dekho
Soch: needle tabhi hilti hai jab current flow kare (magnetic effect). To current flow ho raha hai, yaani liquid conductor hai.
Bulb isliye nahi jala kyunki current bahut weak hai, filament ko glow karne layak garam nahi kar paaya.
Q2. Aman ne galti se iron key ko positive aur copper plate ko negative terminal se connect kar diya. Kya hoga?
Soch aur solution dekho
Soch: coating hamesha negative terminal wale electrode par jamti hai.
Ab negative par copper plate hai, to copper copper plate par hi jamega, key par nahi. Positive terminal wali key ka metal dheere-dheere solution mein jaane lagega aur key kharaab hogi. Sahi method: key negative se, copper plate positive se.
Q3. Poora tap chromium se kyun nahi banaate, sirf chromium ki layer kyun chadhaate hain?
Soch aur solution dekho
Soch: chromium ke faayde (shine, corrosion nahi, scratch nahi) sirf surface par chahiye.
Chromium mehenga hai; poora tap chromium ka banaana bahut costly hoga. Isliye tap sasti metal se banaakar upar se chromium ki thin layer electroplating se chadhaate hain: wahi look aur protection, kam cost mein.
Q4. Ek battery ke terminals par + aur β ke signs mit gaye hain. Sirf ek potato aur do wires se positive terminal kaise pehchaanoge?
Soch aur solution dekho
Step 1: battery ke dono terminals se ek-ek wire connect karo aur dono wires potato mein thodi doori par ghusa do.
Step 2: 20β30 minute rukne ke baad dekho: jis wire ke paas potato mein greenish-blue spot bana, woh wire positive terminal se connected hai.
Reason: current ka chemical effect positive wire ke paas colour change karta hai.
β π charumam.com
π Answer Key (Ek Nazar Mein)
Pehle saare sawaal khud karo, phir yahan milaao. Jahan mistake ho, upar us sawaal ka step-by-step solution dobara padho.
| Section | Answers |
|---|---|
| A. MCQ | 1: (b) Β· 2: (a) Β· 3: (b) Β· 4: (b) Β· 5: (c) Β· 6: (b) Β· 7: (b) Β· 8: (b) Β· 9: (b) Β· 10: (b) |
| B. Fill in the Blanks | 1: chemical Β· 2: electrodes Β· 3: electroplating Β· 4: chromium Β· 5: salt Β· 6: deflect Β· 7: positive Β· 8: 2 |
| C. True / False | 1: F Β· 2: T Β· 3: F Β· 4: T Β· 5: T Β· 6: F Β· 7: F Β· 8: T |
| D. Short Answer | 1: Battery + bulb/LED + wires; free ends liquid mein, glow = conductor Β· 2: Tap water mein salts; distilled mein salt/lemon juice milao Β· 3: Gas bubbles, metal layer, colour change Β· 4: Chromium (shine), tin (food cans), zinc (rust se bachaav) Β· 5: Nahi: weak current, ya loose connection/weak battery Β· 6: 22.4 g |
| E. Long Answer | 1: Copper plate (+), key (β); key par copper layer, plate thin; concentration same Β· 2: Negative: hydrogen 30 mL; positive: oxygen 15 mL Β· 3: Conduct: lemon juice, vinegar, tap water; nahi: distilled water, sugar solution, oil Β· 4: Battery hi; gile haath nahi; waste solution treat karke dispose |
| F. HOTS | 1: Liquid conduct karta hai, par current weak hai Β· 2: Key par coating nahi; key ka metal ghulega, copper plate par copper jamega Β· 3: Chromium mehenga; layer se hi shine aur protection mil jaata hai Β· 4: Greenish-blue spot wala wire = positive terminal |
β π charumam.com
π©βπ« CharuMam Ka Tip
Is unit ke liye ek chhota diagram hamesha banao: battery, do electrodes, aur solution. Phir teen sawaal pucho: (1) kaunsa electrode positive se connected hai aur kaunsa negative se? (2) kis electrode par kya ban raha hai (gas, metal layer)? (3) kyun? Yaad rakho: coating negative par, coating wala metal positive par; water ke electrolysis mein hydrogen negative par, 2 times. Aur safety: experiment sirf battery se! β‘
β π charumam.com
π€ Aur Practice: AI Tutor Se Poochho
Neeche wali line copy karke CharuMam AI Tutor (tutor.charumam.com) mein paste karo. Tutor naye sawaal dega aur mistake pe samjhayega:
β π charumam.com
π Aage Kya?
Ch 4: Electricity: Magnetic and Heating Effects ka hub page jald aa raha hai; tab tak Class 8 Science page (link neeche) se baaki chapters padho. Pichla practice unit Cell: Structure and Functions bhi practice hub pe hai. Agla practice unit: Force and Pressure, jald aa raha hai!
Koi doubt? CharuMam AI Tutor se poochho, ya comment mein likho! π¬
π Post Achha Laga? Like, Share, Subscribe, Follow!
Agar aaj kuch naya samajh aaya, to post ko like kijiye, apne doston aur class ke group mein share kijiye, aur daily naye practice sawaal ke liye humein subscribe aur follow kijiye! π
- π Website: charumam.com
- π€ AI Tutor (doubt poochho, 24Γ7): tutor.charumam.com
- βΆοΈ YouTube (subscribe): @charumamofficial
- πΈ Instagram (follow): @charumamofficial
- βοΈ Telegram: t.me/charumam
- π¬ WhatsApp Channel: CharuMam WhatsApp Channel
- π X (follow): @CharuMamHQ
β π charumam.com
