P-1 Periodic Classification of Element — Science STD 10 — Question

Name the elements, group, formulae and physical state belonging to the halogen family.

Two dissimilar bulbs are connected in series. Which bulb will be brighter? (Hint: Consider the resistance of each bulb.)

A metal combines with a non-metal by the transfer of electrons to form a compound Y.

1. State the type of bonds in Y.
2. What can you say about its melting point and boiling point?
3. Will it be a good conductor of electricity?
4. Will it dissolve in an organic solvent or not?

When a copper coin is dipped in silver nitrate solution, a glitter appears on the coin after some time. Why does this happen? Write the chemical equation.

Find the focal length of a convex lens which produces a virtual image at 10 cm from the lens when an object is placed at 5 cm from the lens.

Which precautions are necessary for proper decomposition of domestic waste?

Alkane and Alkene.

Swarali has got the following observations while doing an experiment. Answer her questions with the help of observations. (Practice Activity Sheet – 2)
Swarali observed that the light bent away from the normal, while travelling from a denser medium to a rarer medium. When Swarali increased the values of the angle of incidence (i). the values of the angle of refraction (r) went on increasing. But at a certain angle of incidence, the light rays returned into the denser medium.
So, Swarali has some questions. Answer them.
(a) Name this certain value of i. What is the value of r at that time?
(b) Name this process of returning light in the denser medium. Explain the process.

Which fuels are obtained from biomass?