On the lines given below, write about what you have learned from the activites done in this lesson. Let me tell you about some of the important things I.ve learned about cells. First, I.ll start with ... __________________

Answer the following questions . a. The earth's magnetic field varies from point is space. Does it also change with time ? It so , on what time scate does it change appreciably ? b. The earth's core is known to contain iron. Yet geologists do not regard this as a source of the earth's magnetism why ? c. The charged currents in the outer conducting regions of the earth's core are thought to be responsible for earth's magnetism . What might be the ' battery ' (i.e., the source of energy) to sustain these currents ? d. The earth may have even reversed the direction of its field several times during its history of 4 to 5 billion years. How can geologists know about the earth's field in such distant past ? e. The earth's field departs from its dipole substantially at large distances (greater than about 30,000 km) what agencies may be responsible for this distortion ? f. Interstellar space has an extremely weak magnetic field of the order of 10^(-12) T, Can such a weak field be of any significant consequence ? Explain. [Note : Exercise 2 is meant mainly to arouse your curiosity . Answers to some question above are tentative or unknown . Brief answers wherever possible are given at the end . For details , you should consult a good text on geomagnetism.]

Both the kidneys of Ravi (28 years) were not functioning and he was undergoing dialysis. He was admitted to a hospital with renal failure. His mother Suganthi (47 years) was willing to donate one of her kidneys to her son after she was given counseling. Their blood groups were matching and later approval was obtained from transplant committee and technical committee. Operation was performed for 5 hrs. He was administered with immunosuppressive drugs and anti inflammatory drugs. He recovered from the operation and returned home. 1. Name the disease Ravi was suffering from. 2. What relation is the donor of the kidney 3. Name the type of matching done to perform the transplant. 4. Why approval has to be got from transplant committee and technical committee? 5. What do you think about Suganthi donating her kidney?

The wavelength of light in the visible region is about 390 nm for violet colour, about 550 nm (average wavelength) for yellowgreen colour and about 760 nm for red colour. (a) What are the energies of photons in (eV) at the (i) violet end, (ii) average wavelength, yellow-green colour, and (iii) red end of the visible spectrum? ("Take h "= 6.63xx10^(-34)" J s and 1 eV" = 1.6xx10^(-19)J.) (b) From which of the photosensitive materials with work functions listed in Table 11.1 and using the results of (i), (ii) and (iii) of (a), can you build a photoelectric device that operates with visible light?

Justify that the line bar(AB) line segment formed by points given in the above three examples is parallel to Y-axis. What can you say about their slope? Why? i) A(-4,2) , B(-4,-2)

Identify the correct statements from the below about "Peroxisomes". (I) peroxisomes identified as organelles by christian de duve. (II) Peroxisomes are small spherical bodies. (III) Leaf cells have many peroxisomes. (IV) Commonly found in liver and kindney of mammals.