| Complete the following chemical equations: |
| (i) \[\mathbf{C}{{\mathbf{H}}_{\mathbf{3}}}\mathbf{+COO}{{\mathbf{C}}_{\mathbf{2}}}{{\mathbf{H}}_{\mathbf{5}}}\mathbf{+NaOH}\to \] |
| (ii) \[\mathbf{C}{{\mathbf{H}}_{\mathbf{3}}}\mathbf{COOH}+\mathbf{NaOH}\to \] |
| (iii) \[{{\mathbf{C}}_{\mathbf{2}}}{{\mathbf{H}}_{\mathbf{5}}}\mathbf{OH}+\mathbf{C}{{\mathbf{H}}_{\mathbf{3}}}\mathbf{COOH}\xrightarrow{Conc.{{\mathbf{H}}_{\mathbf{2}}}\mathbf{S}{{\mathbf{O}}_{\mathbf{4}}}}\] |
| An element P (atomic number 20) reacts with an element Q (atomic number 17) to form a compound. Answer the following questions giving reason: |
| Write the position of P and Q in the Modern Periodic Table and the molecular formula of the compound formed when P reacts with Q. |
| What happens when: |
| (a) Accidently, Planaria gets cut into many pieces? |
| (b) Bryophyllum leaf falls on the wet soil? |
| (c) On maturation sporangia of Rhizopus bursts? |
| State the changes that take place in the uterus when: |
| (a) Implantation of embryo has occurred. |
| (b) Female gamete/egg is not fertilized. |
| Explain with the help of an example each, how the following provide evidences in favour of evolution: |
| (a) Homologous organs |
| (b) Analogous organs |
| (c) Fossils |
| You have been selected to talk on "Ozone layer and its protection" in the school assembly on 'Environment Day.' |
| (a) Why should ozone layer be protected to save the environment? |
| (b) List any two ways that you would stress in your talk to bring in awareness amongst your fellow friends that would also help in protection of ozone layer as well as the environment. |
| (a) Name the organ that produces sperms as well as secretes a hormone in human males. Name the hormone it secretes and write its functions. |
| (b) Name the parts of the human female reproductive system where fertilisation occurs. |
| (c) Explain how the developing embryo gets nourishment inside the mother's body. |
| How do Mendel's experiments show that |
| (a) Traits may be dominant or recessive? |
| (b) Inheritance of two traits is independent of each other? |
| Analyse the following observation table showing variation of image distance \[\mathbf{(v)}\] with object distance \[\mathbf{(u)}\] in case of a convex lens and answer the questions that follow, without doing any calculations: | ||
| S. No. | Object distance u(cm) | Image distance v(cm) |
| 1. | \[-90\] | \[+18\] |
| 2. | \[-60\] | \[+20\] |
| 3. | \[-30\] | \[+30\] |
| 4. | \[-20\] | \[+60\] |
| 5. | \[-18\] | \[+90\] |
| 6. | \[-10\] | \[+100\] |
| (a) What is the focal length of the convex lens? Give reason in support of your answer. | ||
| (b) Write the serial number of that observation which is not correct. How did you arrive at this conclusion? | ||
| (c) Take an appropriate scale to draw ray diagram for the observation at S. No. 4 and find the approximate value of magnification. | ||
| (a) To construct a ray diagram we use two rays which are so chosen that it is easy to know their directions after reflection from the mirror. List two such rays and state the path of these rays after reflection in case of concave mirrors. Use these two rays and draw ray diagram to locate the image of an object placed between pole and focus of a concave mirror. |
| (b) A concave mirror produces three times magnified image on a screen. If the object is placed 20 cm in front of the mirror, how far is the screen from the object? |
| (a) Draw a ray diagram to explain the term angle of deviation. |
| (b) Why do the component colours of incident white light split into a spectrum while passing through a glass prism, explain. |
| (c) Draw a labelled ray diagram to show the formation of a rainbow. |
| You have four test tubes. A, B, C and D containing sodium carbonate, sodium chloride, lime water and blue litmus solutions respectively. Out of these the material of which test tube/test tubes would be suitable for the correct test of acetic/ethanoic acid? |
| (a) Only A |
| (b) A and B |
| (c) B and C |
| (d) A and D |
| For demonstrating the preparation of soap in the laboratory which of the following combination of an oil and a base would be most suitable? |
| (a) Mustard oil and calcium hydroxide |
| (b) Castor oil and calcium hydroxide |
| (c) Turpentine oil and sodium hydroxide |
| (d) Mustard oil and sodium hydroxide. |
| A student took four test tubes P, Q, R and S and filled about 8 ml. of distilled water in each after that he dissolved an equal amount of \[\mathbf{N}{{\mathbf{a}}_{\mathbf{2}}}\mathbf{S}{{\mathbf{O}}_{\mathbf{4}}}\] in P, \[{{\mathbf{K}}_{\mathbf{2}}}\mathbf{S}{{\mathbf{O}}_{\mathbf{4}}}\] in Q, \[\mathbf{CaS}{{\mathbf{O}}_{\mathbf{4}}}\] in R and \[\mathbf{MgS}{{\mathbf{O}}_{\mathbf{4}}}\]in. On adding an equal amount of soap solution and shaking each test tube well, a good amount of lather will be obtained in the test tubes: |
| (a) P and Q |
| (b) P and R |
| (c) P, Q and S |
| (d) Q, R and S |
| A student while observing an embryo of a gram seed listed various parts of the embryo as listed below: |
| Testa, Micropyle, Cotyledon, Tegmen, Plumule, Radicle. On examining the list the teacher commented that only three parts are correct. Select these three correct parts: |
| (a) Cotyledon, Testa, Flumule |
| (b) Cotyledon, Plumule, Radicle |
| (c) Cotyledon, Tegmen, Radicle |
| (d) Cotyledon, Micropyle, Plumule |
| Select the set of homologous organs from the following: |
| (a) Wings of pigeon and a butterfly |
| (b) Wings of bat and a pigeon |
| (c) Forelimbs of cow, a duck and a lizard |
| (d) Wings of butterfly and a bat |
| Three students A, B and C focussed a distant building on a screen with the help of a concave mirror. To determine focal length of the concave mirror they measured the distances as given below |
| Student A: From mirror to the screen |
| Student B: From building to the screen |
| Student C: From building to the mirror |
| Who measured the focal length correctly? |
| (a) Only A |
| (b) Only B |
| (c) A and B |
| (d) B and C |
| If you focus the image of a distant object, whose shape is given below, on a screen using a convex lens. |
 |
| The shape of the image of this object on the screen would be: |
(a)  |
(b)  |
(c)  |
(d)  |
| In the following diagram the correctly marked angles are: |
 |
| (a) \[\angle \]A and \[\angle \]e |
| (b) \[\angle \]i,\[\angle \]A and\[\angle \]D |
| (c) \[\angle \]A, \[\angle \]i and \[\angle \]e |
| (d) \[\angle \]A/\[\angle \]r and\[\angle \]D |
| The correct sequencing of angle of incidence, angle of emergence, angle of refraction and lateral displacement shown in the following diagram by digits 1, 2, 3 and 4 is: |
 |
| (a) 2, 4, 1, 3 |
| (b) 2, 1, 4, 3 |
| (c) 1, 2, 1, 4, 3 |
| (d) 2, 1, 3, 4 |
| A student places a candle flame at a distance of about 60 cm from a convex lens of focal length 10 cm and focuses the image of the flame on a screen. After that he gradually moves the flame towards the lens and each time focuses the image on the screen. |
| (a) In which direction-toward or away from the lens, does he move the screen to focus the image? |
| (b) How does the size of the image change? |
| (c) How does the intensity of the image change as the flame moves towards the lens? |
| (d) Approximately for what distance between the flame and the lens, the image formed on the screen is inverted and of the same size? |
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