The mean value can be calculated from both ungrouped and grouped data. Which one do you think is more accurate? Why?

Why is the colour of a leaf kept in the dark frequently yellow or pale green ? Which pigment do you think is more stable ?

There are two bags each of which contains n balls. A man has to select an equal number of balls from both the bags. Prove that the number of ways in which a man can choose at least one ball from each bag is^(2n)C_n-1.

RuBisCO is an enzyme that acts both as a carboxylase and oxygenase. Why do you think RuBisco carries out more carboxylation in C_(4) plants ?

When a DC voltage is applied at the two ends of a circuit kept in a closed box, it is observed that the current gradually increases from zero to a certain value and then remains constant . What do you think that the circuit contais?

Nitration is an example of aromatic electrophilic substitution and its rate depends upon the group already present in the benzene ring. Out of benzene and phenol, which one is more easily nitrated and why ?

Aminoacids, as the name suggests, have both an amino group and a carboxyl group in their structure. In addition, all naturally occurring aminoacids (those which are found in proteins) are called L-aminoacids. From this, can you guess from which compound can the simplest aminoacid be made

A rainbow ordinarily show a range of colours. But if the water droplets that from the rainbow are small enough, the rainbow will appear white. Explain why, using diffraction ideas. How small do you think the raindrops would have to be for this to occur?

A resistance R = 2Omega is connected to one of the gaps in a metre bridge, which uses a wire of length 1m. An unknown resistance X is connected in the other gap as shown in the figure. The balance point is noticed at 'l' from the positive end of the battery. On interchanging R and X, it is found that the balance point further shifts by 20 cm (away from end A). Neglecting the end correction, calculate the value of unknown resistance X used.