How is a voltmeter connected in the circuit to measure the potential difference between two points?

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 atom has electronic configuration 2, 8, 7.

   (a)  What is the atomic number of this element?
   (b)  To which of the following elements would it be chemically similar? (Atomic numbers are given in parentheses.)
          N(7)      F(9)      P(15)      Ar(18)

In evolutionary terms, we have more in common with

(a) a Chinese school-boy.
(b) a chimpanzee.
(c) a spider.
(d) a bacterium.

Give an example of a metal which

  (i) is a liquid at room temperature.
  (ii) can be easily cut with a knife.
  (iii) is the best conductor of heat.
  (iv) is a poor conductor of heat.

How does the creation of variations in a species promote survival?

What is an homologous series? Explain with an example.

Identify the substances that are oxidised and the substance that are reduced in the following reactions.

    (i)    4Na(s)   +   O₂(g)    →    2Na₂O(s)
    (ii)   CuO(s)   +   H₂(g)    →    Cu(s)   +   H₂O(l)

What are the necessary conditions for autotrophic nutrition and what are its by-products?

How is the movement of leaves of the sensitive plant different from the movement of a shoot towards light?

Why is the amount of gas collected in one of the test tubes in Activity 1.7 double of the amount collected in the other? Name this gas.

List the properties of magnetic field lines.