if any one have important question for science exam 2019 class 10th
please help their is many questions
Answers
Answered by
0
*Science*
Q1. Explain why a ray of light passing through the centre of curvature of concave minor gets reflected along the same path?
Q2. Dark reaction of photosynthesis does not need light. Do plants undergo dark reaction at night? Explain.
Q3. How are we able to see distant and nearby objects clearly? Which part of eye helps in changing curvature of lens? Why no image is formed at blind spot?
Q4. (a) Which property of carbon leads to formation of large number of compounds? Define it.
(b) What is the functional group in the following molecules?
(i) CH3CH2CH2OH
(ii) CH3COOH
Q5. (a) Why magnification is taken negative for real images and positive for virtual images?
(b) Why convex mirror is used in rear view mirrors and not concave mirror?
Q6. (a) What are ‘magnetic field lines’? How is the direction of a magnetic field at a point determined ?
(b) Draw two field lines around a bar magnet along its length on its two sides and mark the field directions on them by arrow marks.
Q7. (a) Mention the pH range within which our body works. Explain how antacids give relief from acidity. Write the name of one such antacid.
(b) Fresh milk has a pH of 6. How does the pH will change as it turns to curd? Explain your answer.
(c) A milkman adds a very small amount of baking soda to fresh milk. Why does this milk take a longer time to set as curd?
(d) Mention the nature of toothpastes. How do they prevent tooth decay?
Q8. Atoms of eight elements A. B. C. D, E, F. G and H have the same number of electronic shells but different number of electrons in their outermost shell. It was found that elements A and G combine to form an ionic compound. This compound is added in a small amount to almost all vegetable dishes during cooking. Oxides of elements A and B are basic in nature while those of E and F are acidic. The oxide of D is almost neural. Based on the above information answer the following questions:
(i) To which group or period of the periodic table do the listed elements belong?
(ii) What would be the nature of compound formed by a combination of elements B and F?
(iii) Which two of these elements could definitely be metals?
(iv) Which one of the eight elements is most likely to be found in gaseous state at room temperature?
(v) If the number of electrons in the outermost shell of elements C and G are 3 and 7 respectively, write the formula of the compound formed by the combination of C and G.
Q9. Mention the essential material (chemicals) to prepare soap in the laboratory. Describe in brief the test of determining the nature (acidic/alkaline) of the reaction mixture of saponification reaction.
Q10. Write two precautions to be taken while identifying different parts of an embryo of a dicot seed.
Ans. (i) The slide should be properly focused.
(ii) Slide should be observed first under low-power magnification and then under high-power magnification of the compound microscope.
Q11. A student is to conduct an experiment to show CO2 is released during respiration. List two precautions that he/she must take for obtaining correct observation.
Ans. Two precautions to be taken are:
(i) Germinating seeds (living) should be used.
(ii) The experiment set up must be air-tight.
Q12. What is the important function of presence of ozone in earth’s atmosphere?
Ans. Ozone is the Earth’s natural process for all life forms. It shields our planet from the UV radiations, as these ultraviolet rays are harmful for all the living things. Therefore, any change in the size of this layer will automatically affect the life of people, plants and animals living on earth.
(These are a few important questions, hope it helps.)
Thankyou!!!
Q1. Explain why a ray of light passing through the centre of curvature of concave minor gets reflected along the same path?
Q2. Dark reaction of photosynthesis does not need light. Do plants undergo dark reaction at night? Explain.
Q3. How are we able to see distant and nearby objects clearly? Which part of eye helps in changing curvature of lens? Why no image is formed at blind spot?
Q4. (a) Which property of carbon leads to formation of large number of compounds? Define it.
(b) What is the functional group in the following molecules?
(i) CH3CH2CH2OH
(ii) CH3COOH
Q5. (a) Why magnification is taken negative for real images and positive for virtual images?
(b) Why convex mirror is used in rear view mirrors and not concave mirror?
Q6. (a) What are ‘magnetic field lines’? How is the direction of a magnetic field at a point determined ?
(b) Draw two field lines around a bar magnet along its length on its two sides and mark the field directions on them by arrow marks.
Q7. (a) Mention the pH range within which our body works. Explain how antacids give relief from acidity. Write the name of one such antacid.
(b) Fresh milk has a pH of 6. How does the pH will change as it turns to curd? Explain your answer.
(c) A milkman adds a very small amount of baking soda to fresh milk. Why does this milk take a longer time to set as curd?
(d) Mention the nature of toothpastes. How do they prevent tooth decay?
Q8. Atoms of eight elements A. B. C. D, E, F. G and H have the same number of electronic shells but different number of electrons in their outermost shell. It was found that elements A and G combine to form an ionic compound. This compound is added in a small amount to almost all vegetable dishes during cooking. Oxides of elements A and B are basic in nature while those of E and F are acidic. The oxide of D is almost neural. Based on the above information answer the following questions:
(i) To which group or period of the periodic table do the listed elements belong?
(ii) What would be the nature of compound formed by a combination of elements B and F?
(iii) Which two of these elements could definitely be metals?
(iv) Which one of the eight elements is most likely to be found in gaseous state at room temperature?
(v) If the number of electrons in the outermost shell of elements C and G are 3 and 7 respectively, write the formula of the compound formed by the combination of C and G.
Q9. Mention the essential material (chemicals) to prepare soap in the laboratory. Describe in brief the test of determining the nature (acidic/alkaline) of the reaction mixture of saponification reaction.
Q10. Write two precautions to be taken while identifying different parts of an embryo of a dicot seed.
Ans. (i) The slide should be properly focused.
(ii) Slide should be observed first under low-power magnification and then under high-power magnification of the compound microscope.
Q11. A student is to conduct an experiment to show CO2 is released during respiration. List two precautions that he/she must take for obtaining correct observation.
Ans. Two precautions to be taken are:
(i) Germinating seeds (living) should be used.
(ii) The experiment set up must be air-tight.
Q12. What is the important function of presence of ozone in earth’s atmosphere?
Ans. Ozone is the Earth’s natural process for all life forms. It shields our planet from the UV radiations, as these ultraviolet rays are harmful for all the living things. Therefore, any change in the size of this layer will automatically affect the life of people, plants and animals living on earth.
(These are a few important questions, hope it helps.)
Thankyou!!!
Answered by
0
Here is your answer mate,
Homologous series,difference between soaps and detergents, newlands law, Mendeleev's periodic table,difference b/w aerobic and anaerobic respiration,opening and closing of stomata,binary fission,female and male reproductive system ,break down of glucose by various path ways, heart , excretory system,reflex arc,human brain, difference between asexual and sexual reproduction, Mendel's experiment,laws of inheritance,difference between acquired and inherited traits,ray diagrams,laws of reflection and retraction,defects of vision and their correction, atmospheric refraction,scattering of light, ohm's law,resistors, electric motor and generator,field lines around bar magnet, Fleming's Left hand rule, bio gas plant, solar cooker,10% law,dams.
Hope it helps ......
Plz mark as brainliest........
Similar questions