As shown in the figure below A and B are two lamps. Lamp A is rated at 12 V, 24W. Lamp B is rated at 6.0 V. When lamp B operates at its rated voltage, the current in it is 3.0 A. The values of R₁ and R₂ are chosen so that both lamps operate at their rated voltages.

Based on the information given, answer the following.

(a) Calculate the current in Lamp A.

(b) State and give reason for the reading of the Voltmeter.

(c) Calculate the resistance of R₂.

(d) Find the value of the resistance R₁.

(a) State Joules law of heating and write its mathematical expression.

(b) Two resistors of resistances 2 Ω and 4 Ω are connected in

1. series
2. parallel

with a battery of given potential difference. Compute the ratio of total quantity of heat produced in the combination in the two cases if the total voltage and time are kept the same for both.

(a) Distinguish between ethanol and ethanoic acid experimentally.

Attempt either subpart B or C.

(b) Give the IUPAC name of the first member of Alkene which is formed by addition of conc. sulphuric acid to it. Illustrate the change with the help of a chemical equation.

OR

(c) “All combustion reactions are oxidation but all oxidation reactions are not combustion.” Justify.

Mohan and Rohit observed that shoots of a plant growing in shade bend towards the sunlight. Whereas, leaves of ‘Touch me not’ plant fold and droop soon after touching. They were curious to know how these movements occur in plants.

In order to help them understand the movements in the plants, answer the following questions:

Attempt either subpart A or B.

(a) What causes the bending of shoots in the plants as shown in figure A?

OR

(b) What causes the folding of the leaves in ‘Touch me not’ plant as shown in figure B?

(c) Compare the movement of growth of the pollen tube towards ovule with the movements shown in part A of the above figure.

(d) Compare the movement shown in figure B with the movement of body parts in the animals.