Exercise-Choice

The general formula of three compounds $\mathrm{A}, \mathrm{B}$ and $\mathrm{C}$ is ${\mathrm{C}}_{\mathrm{n}}{\mathrm{H}}_{2\mathrm{n}}$. $\mathrm{B}$ has the highest boiling point and $\mathrm{C}$ has the lowest boiling point.

Name the homologous series to which $\mathrm{A}, \mathrm{B}$ and $\mathrm{C}$ belong.

Write the name of unsaturated hydrocarbons which contains: 
(a) one or more double bonds. 
(b) one or more triple bonds. 
 

Light enters from air to glass having refractive index $1.50$. What is the speed of light in the glass? The speed of light in a vacuum is $3\times {10}^8 \raisebox{1ex}{$\mathrm{m}$}\!\left/ \!\raisebox{-1ex}{$\mathrm{s}$}\right.$.

List the factors that affect the strength of an electromagnet.

Construct two tables, with the headings asexual and sexual reproduction. Write each of these statements in the correct column.

• Only one parent involved
• one or two parents involved 
• involves gametes
• involves fertilisation
• zygote formed
• all offspring genetically identical
• genetic variation among offspring

Name the process by which an amoeba reproduces. Draw the various stages of its reproduction in a proper sequence.

Explain the working of a steam turbine.

An object of size $70 \mathrm{mm}$ is place at $27 \mathrm{cm}$ in front of a concave mirror of focal length $18 \mathrm{cm}$.  At what distance from the mirror should a screen be placed so that a sharp focussed image can be obtained? Find the size and nature of the image.