An electric oven of 2 kW power rating is operated in a domestic electric circuit (220 V) that has a current rating of 5 A. What result do you expect? Explain.

When a 12 V battery is connected across an unknown resistor, there is a current of 2.5 mA in the circuit. Find the value of the resistance of the resistor.

Outline a project which aims to find the dominant coat colour in dogs.

Draw the structure for the following compounds.                

       (i)    Ethanoic acid             (ii)   Bromopentane*
       (iii)  Butanone                   (iv)   Hexanal.

*Are structural isomers possible for bromopentane?

A hot plate of an electric oven connected to a 220 V line has two resistance coils A and B, each of 24 Ω resistance, which may be used separately, in series, or in parallel. What are the currents in the three cases?

How is the sex of the child determined in human beings?

(a)  What property do all elements in the same column of the Periodic Table as boron have in common?
(b)  What property do all elements in the same column of the Periodic Table as fluorine have in common?

Calculate the number of electrons constituting one coulomb of charge.

What is an homologous series? Explain with an example.

Why is variation beneficial to the species but not necessarily for the individual?

A man with blood group A marries a woman with blood group O and their daughter has blood group O. Is this information enough to tell you which of the traits – blood group A or O – is dominant? Why or why not?

An electric motor takes 5 A from a 220 V line. Determine the power of the motor and the energy consumed in 2 h.

What are oxidising agents?

Two circular coils A and B are placed closed to each other. If the current in the coil A is changed, will some current be induced in the coil B? Give reason.

Find the focal length of a convex mirror whose radius of curvature is 32 cm.

Why does the sky appear dark instead of blue to an astronaut?

How is the small intestine designed to absorb digested food?

Why is it necessary to separate oxygenated and deoxygenated blood in mammals and birds?

Find out, from Table 10.3, the medium having highest optical density. Also find the medium with lowest optical density.

     Table 10.3 Absolute refractive index of some material media

What evidence do we have for the origin of life from inanimate matter?

How do we detect the smell of an agarbatti (incense stick)?