P-1 Lenses — Science STD 10 — Question

With the help of an example, explain how variation leads to evolution.

Repeat the activity “Refraction of light passing through a glass slab by replacing the glass slab by a transparent plastic slab.
(i) What similarity do you observe?
(ii) What difference do you notice?

A tapping vessel opens in a tank like container that is tapering on the lower side. The tank has an outlet for water on the upper side and a water inlet on the lower side. Finely ground ore is released in the tank. A forceful jet of water is introduced in the tank from lower side and gangue particles and pure ore are separated by this method.
(i) The above description is of which gravitation separation method?
(ii) Draw labelled diagram of this method. (March 2019)

In case of sexual reproduction, newborn show similarities about characters. Explain this statement with suitable examples.

What is overloading? When does it occur? What does it cause? How can overloading be avoided?

In what respects do the properties of group 1 elements differ from those of group 17 elements? Explain with examples by taking one element from each group.

what are (i) free fall, (ii) acceleration due to gravity (iii) escape velocity (iv) centripetal force?

In terms of electronic configurations, explain the variation in the size of the atoms of the elements belonging to the same period and same group.

Divide the metals Cu, Zn, Ca, Mg, Fe, Na, Li into three groups, namely reactive metals, moderately reactive metals and less reactive metals.

Write down the reasons, effects and remedial measures taken for any one disaster seen or heard by you.