(a) Name two isotopes of uranium which are fissionable.
(b) Which of the isotope mentioned in part (a) above is easily fissionable ? Give reason. (c ) State whether the neutron needed for fission reaction of the isotope mentioned in part (b) above, is slow or fast ?

Which of the above two graphs : (a) and (b)the human voice is likely to be the male voice ? Give reason for your answer. .

The diagram given below is that of a structure present in a human kidney. Study the same and answer the questions that follows : (i) Name the structure represented in the diagram. (ii) What is the liquid entering part T called? Name two substances present in this liquid that are reabsorbed in the tubule. (iii) What is the fluid that comes to part '2' called? Name the main nitrogenous waste in it. (iv) Mention the three main steps involved in the formation of the fluid mentioned in (iii) above. (v) Name the substance which may be present in the fluid part '11 if a person suffer from diabetes mellitus.

(a) Write one nuclear fusion reaction. (b) State the approximate value of energy released in the reaction mentioned in part (a). (c ) Give reason for the release of energy stated in part (b).

A person is unable to see objects distinctly placed within 50 cm from his eyes. (a) Name the defect of vision the person is suffering from and list its two possible causes. (b) Draw ray diagram to show the defect in the above case. (c) Mention the type of lens used by him for the correction of the defect and calculate its power. Assume that the near point for the normal eye is 25 cm. (d) Draw a labelled diagram for the correction of the defect in the above case.

The ore of Uranium found in nature contains ""_(92)^(238)U and ""_(92)^(235)U . Although both the isotopes are fissionable, it is found out experimentally that one of the two isotopes is more easily fissionable. Name the isotope of Uranium which is easily fissionable

The ore of uranium found in nature contains ""_(92)U^(238)and""_(92)U^(235) . Although both the isotopes are fissionable, it is found out experimentally that one of the two isotopes is more easily fissionable. Give a reason for your answer.

(a) What is a calorimeter ? (b) Name the material of which it is made of. Give two reasons for using the material stated by you.

(a) Name the two growth models that represent population growth and draw the respective growth curves they represent. (b) State the basis for the difference in the shape of these curves. (c) Which one of the curves represent the human population growth at present? Do you think such a curve is sustainable ? Give reason in support of your answer.

(a) Name the two growth models that represent population growth and draw the respective growth curves they represent. (b) State the basis for the difference in the shape of these curves. (c) Which one of the curves represent the human population growth at present? Do you think such a curve is sustainable ? Give reason in support of your answer.

The ore of uranium found in nature contains ""_(92)U^(238)and""_(92)U^(235) . Although both the isotopes are fissionable, it is found out experimentally that one of the two isotopes is more easily fissionable. Write a nuclear reaction when Uranium 238 emits an alpha particle to form a Thorium (Th) nucleus.