Light – Reflection and Refraction — Science STD 10 — Question

Describe the process of fertilisation in a flower with the help of labelled diagrams.

Draw a diagram to show the refraction of light through a glass prism. On this diagram, mark:

1. Incident ray.
2. Emergent ray, and.
3. Angle of deviation.

How does a universal indicator work?

Carbon, Group (14) element in the Periodic Table, is known to form compounds with many elements.
Write an example of a compound formed with,

1. Chlorine (Group 17 of Periodic Table)
2. Oxgygen (Group 16 of Periodic Table)

Give the names and formulae of two strong bases and two weak bases.

What is biogas? Why is biogas considered an ideal fuel for domestic use?

The atoms of copper contain electrons and the atoms of rubber also contain electrons. Then why does copper conduct electricity but rubber does not conduct electricity?

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.

1. In which direction-toward or away from the lens, does he move the screen to focus the image?
2. How does the size of the image change?
3. How does the intensity of the image change as the flame moves towards the lens?
4. Approximately for what distance between the flame and the lens, the image formed on the screen is inverted and of the same size?

1. Find the nature, position and magnification of the images formed by a convex lens of focal length 0.20 m if the object is placed at a distance of:

1. 0.50m
2. 0.25m
3. 0.15m

2. Which of the above cases represents the use of convex lens in a film projector, in a camera, and as a magnifying glass?

What is the name given for the substance that reacts and forms in a chemical reaction?