Class 10 > PYQ SCIENCE > 2012 > SET B


History 2 Views

State one function of pupil in human eye.

State one harmful effect of depletion of ozone layer on the living organisms of the ecosystem.

“DNA copies generated during reproduction will be similar but may not be identical to the original.” Justify the statement.

The formula of magnesium oxide is MgO. State the formula of barium nitrate and barium sulphate, if barium belongs to the same group as magnesium.

(a) Which two criteria did Mendeleev use to classify the elements in his periodic table?
(b) Which element of period ‘3’ of the modem periodic table
is the most reactive non-metal?
is the most reactive metal?
forms ion with -2 charge?
forms ion with +2 charge?

Define the term, dispersion of white light. State the colour which bends the least,
the most, while passing through a glass prism. Draw the dispersion of light through prism.

“The father is responsible for the sex of a child, not the mother.” Justify this statement.

(a) How are the following related?
(i) Number of valence electrons of different elements in the same group.
(ii) Number of shells of elements in the same period.
(b) How do the following change?
(i) Number of shells of elements as we go down a group.
(ii) Number of valence electrons of elements on moving from left to right in a period.
(iii)Atomic radius in moving from left to right along a period.
(iv)Atomic size down a group.