Metals and Non-Metals — Science STD 10 — Question

Why is sustainable management of natural resources necessary? Out of the two methods–reuse and recycle–which one would you suggest to practise and why?

A plant has two varieties, one with red petals and the other with white petals. When these two varieties are cross-pollinated, all the offsprings have red petals?

1. Which gene is dominant?
2. Choose suitable letters to represent the two genes.

Discuss the case when a convex lens forms a virtual and enlarged image.

What is the fundamental difference in the electronic configurations between the group 1 and group 2 elements?

Name an indicator which is:

1. Pink in acidic solution and yellow in basic solution.
2. Colourless in acidic solution and pink in basic solution.

Draw a ray diagram to show the path of the reflected ray corresponding to an incident ray which is directed towards the principal focus of a convex. mirror. Mark on it the angle of incidence and the angle of reflection.

When the leaves of a sensitive plant are touched with a finger, they fold up and when light fades at dusk, the petals of a dandelion flower close.

1. State one way in which the above two processes are similar.
2. State two ways in which the above two processes differ.

Metals X and Y can be recovered from the anode mud left behind after the electrolytic refining of copper metal. The coins made of metal X look new even after several years of use but the coins made of metal Y lose their shine gradually and get blackened soon. When metal X is alloyed with a small amount of metal Y, it becomes hard and hence suitable for making ornaments. What are metals X and Y ? Also state the colour of metal X.

Your friend can read a book perfectly well but cannot read the writing on blackboard unless she sits on the front row in class.

1. Is she short-sighted or long-sighted?
2. What type of lenses-converging or diverging-would an optician prescribe for her?

A certain form of energy which is not sourced directly or indirectly from the sun and does not cause any pollution is very easily converted into electricity. This form of energy is, however, not available everywhere. Moreover, it is technically very difficult and expensive to obtain it. Name the form of energy.