CBSE chemistry class12 Sample paper set- 5 with answer key

 

CBSE chemistry class12 Sample paper set- 4 with answer key

 

CBSE chemistry class12 Sample paper set-3 with answer key

 

CBSE chemistry class12 Sample paper set- 2 with answer key

 

CBSE chemistry class12 Sample paper set- 1 with answer key

 

Matter in Our Surroundings quiz-1

Matter in Our Surroundings

Quiz

 

1. In which of the following conditions, the distance between the molecules of hydrogen gas would increase?
   (i) Increasing pressure on hydrogen contained in a closed container
   (ii) Some hydrogen gas leaking out of the container
   (iii) Increasing the volume of the container of hydrogen gas
   (iv) Adding more hydrogen gas to the container without increasing the volume of the container
   1.   (i) and (iii)
   2.   (i) and (iv)
   3.   (ii) and (iii)
   4.   (ii) and (iv)
2. When a gas jar full of air is placed upside down on a gas jar full of bromine vapours, the red-brown vapours of bromine from the lower jar go upward into the jar containing air. In this experiment:
   1.   Air is heavier than bromine
   2.   Both air and bromine have the same density
   3.   Bromine is heavier than air
   4.   Bromine cannot be heavier than air because it is going upwards against gravity
3. A form of matter has no fixed shape but it has a fixed volume. An example of this form of matter is
   1.   Krypton
   2.   Kerosene
   3.   Carbon steel
   4.   Carbon dioxide
4. Which one of the following statements is not true?
   1.   The molecules in a solid vibrate about a fixed position
   2.   The molecules in a liquid are arranged in a regular pattern
   3.   The molecules in a gas exert negligibly small forces on each other, except during collisions
   4.   The molecules of a gas occupy all the space available
5. The correct procedure of heating iron-sulphur mixture to prepare iron sulphide is:
   1.   Heat the powder mixture at the base of the test tube using a blue flame throughout.
   2.   Heat the iron filings and sulphur mixture in the middle of the test tube using yellow flame throughout.
   3.   Heat the powder mixture at the top of the test tube using an orange flame throughout.
   4.   Heat the iron filings-sulphur mixture at 3/4 quarters of the test tube using a red flame throughout.
6. When water at 0°C freezes to form ice at the same temperature of 0°C, then it:
   1.   Absorbs some heat
   2.   Releases some heat
   3.   Neither absorbs nor releases heat
   4.   Absorbs exactly 3.34 x 105J/kg of heat
7. When heat is constantly supplied by a burner to boiling water, then the temperature of water during vaporisation :
   1.   Rises very slowly
   2.   Rises rapidly until steam is produced
   3.   First rises and then becomes constant
   4.   Does not rise at all
8. Which one of the following set of phenomena would increase on raising the temperature?
   1.   Diffusion, evaporation, compression of gases
   2.   Evaporation, compression of gases, solubility
   3.   Evaporation, diffusion, expansion of gases
   4.   Evaporation, solubility, diffusion, compression of gases
9. On converting 308 K, 329 K and 391 K to Celsius scale, the correct sequence of temperatures will be:
   1.   33°C, 56°C and 118°C
   2.   35°C, 56°C and 119°C
   3.   35°C, 56°C and 118°C
   4.   56°, 119°C and 35° C
10. Which of the following phenomena always results in the cooling effect?
    1.   Condensation
    2.   Evaporation
    3.   Sublimation
    4.   None of these
11. Which of the following cannot be considered a form of matter?
    1.   Atom
    2.   Water
    3.   Humidity
    4.   Electron
12. Which of the following causes the temperature of a substance to remain constant while it is undergoing a change in its state?
    1.   Latent heat
    2.   Lattice energy
    3.   Loss of heat
    4.   None of these
13. Which of the following statement is correct?
    1.   Materials existing as liquids at room temperature have their melting and boiling points lower than that of room temperature.
    2.   The phenomenon involving the transition of a substance from solid to liquid state is called sublimation.
    3.   To convert a temperature on the Celsius scale to Kelvin scale, subtract 273 from the given temperature
    4.   The density of ice is less than that of water.
14. Which of the following statement is not true regarding the characteristic of matter?
    1.   Particles of a matter are randomly moving in all directions.
    2.   Kinetic energy of the particles increases with a rise in temperature
    3.   Kinetic energy of the particles of all maters remains the same at a particular temperature.
    4.   Particles of matter diffuse into each other on their own.

World TB Day: 2021

 विश्व टीबी दिवस : 2021  

थीम 2021 : “द क्लॉक इज टिकिंग” - जिसका अर्थ है, वैश्विक मंच पर नेताओं द्वारा टीबी के उन्मूलन हेतु की गई प्रतिबद्धताओं पर कार्य करने के लिए दुनिया समय से पीछे हो चली है और COVID-19 महामारी के कारण “End TB progress” की गति नि:संदेह धीमी हुई है। 

अब ज़िम्मेदारी बढ़ जाती है कि यूनिवर्सल हेल्थ कवरेज प्राप्त करने की दिशा में डब्ल्यूएचओ की नीति अनुसार इस बिमारी की रोकथाम व देखभाल हेतु सुविधाओं तक सभी की समान पहुँच बनी रहे। 

उद्देश्य :-

•  प्रत्येक वर्ष दुनिया में 24 मार्च को टीबी (क्षय रोग) के स्वास्थ्य, सामाजिक व आर्थिक दुष्परिणामों के बारे में सार्वजनिक जागरूकता बढ़ाने तथा वैश्विक स्तर पर टीबी जैसी महामारी का समूल नाश करने के प्रयासों को बढ़ाने हेतु।

शुरुआत :-

•  वर्ष 1882 में डॉ. रॉबर्ट कोच द्वारा टीबी का कारण बनने वाले जीवाणु की खोज तथा बीमारी के निदान व इलाज का रास्ता खोल दिए जाने की घोषणा के दिन को ही बतौर विश्व टीबी दिवस चिन्हित किया गया था।

•  टीबी दुनिया की सबसे घातक संक्रामक बीमारियों में से एक है। जिसके कारण हर दिन करीब 4 हज़ार लोग अपनी जान गंवा बैठते हैं तो वहीं दूसरी ओर लगभग 28 हज़ार लोग इलाज योग्य इस बीमारी से ग्रस्त हो जाते हैं। 

•  वर्ष 2000 से लेकर अब तक टीबी से निपटने के लिए किए गए वैश्विक प्रयासों द्वारा अनुमानित तौर पर 63 मिलियन लोगों की जानें बचाई जा चुकी हैं।