Q28 of 30 Page 1

(a) Draw a diagram showing germination of pollen on stigma of a flower and mark on it the following organs/parts:

(i) Pollen Grain


(ii) Pollen tube


(iii) Stigma


(iv) Female germ cell


(b) State the significance of pollen tube.


(c) Name the parts of flower that develop after fertilization into


(i) Seed


(ii) Fruit


OR


(a) Use of a condom is beneficial for both the sexes involved in a sexual act." Justify this statement giving two reasons.


(b) How do oral contraceptive help in avoiding pregnancies?


(c) What is sex selective abortion? How does it affect a healthy society? (State any one consequence)


(a)


(b) Pollen tube carries the male gametes to the egg cell


(c) (i) ovule changes to seed


(ii) ovary changes to fruit


OR


(a) Condoms prevent sexually transmitted diseases and unwanted pregnancies hence is advantageous to both


(b) Oral contraceptives upset the hormonal balance hence prevent production or /and release od ovum


(c) Sex selective abortion is when upon knowing the sex of the child one decides to abort it. Female foeticide is a grave setback to it.


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26

(a) Compare soaps and detergents on the basis of their composition and cleansing action in hard water.

(b) What happens when ethanol is treated with sodium metal? State about the behaviour of ethanol in this reaction.


(c) Draw the structure of cyclohexane.


(d) Name the following compound



27

(a) Write the correct sequence of steps followed during journey of oxygen rich blood from lungs to various organs of human body.

(b) What happens when the system of blood vessels develops a leak?


 29

(a) For the combination of resistors shown in the following figure, find the equivalent resistance between M & N.


(b) State Joule's law of heating.


(c) Why we need a 5 A fuse for an electric iron which consumes 1 kW power at 220 V?


(d) Why is it impracticable to connect an electric bulb and an electric heater in series?


 30

(a) A security mirror used in a big showroom has radius of curvature 5 m. If a customer is standing at a distance of 20, from the cash counter, find the position, nature and size of the image formed in the security mirror.

(b) Neha visited a dentist in his clinic. She observed that the dentist was holding an instrument fitted with a mirror. State the nature of this mirror and reason for its use in the instrument used by dentist.


OR


Rishi went to a palmist to show his palm. The palmist used a special lens for this purpose.


(i) State the nature of the lens and reasons for its use.


(ii) Where should the palmist place/hold the lens so as to have a real and magnified image of an object?


(iii) If the focal length of this lens is 10 cm, the lens is held at a distance of 5 cm from the palm, use lens formula to fine the position and size of the image.