The circuit depicted in the figure is employed for studying Ohm's Law. Instead of using a standard resistor, a student opts for a glass tube filled with mercury (tube 1), connected to the circuit through two electrodes E1 & E2. He records the readings of the ammeter and voltmeter, thereby calculates the resistance. The student repeats the experiment by substituting tube 1 with tube 2, where the same amount of mercury fills the tube 2.

Neglecting internal resistance of the cell use (> or < or =) to compare

(a) the resistance in both the cases.

(b) the voltmeter readings in both the cases.

(c) the specific resistance in both the cases.

A radioactive nucleus X emits an alpha particle followed by two beta particles to form nucleus Y.

(a) With respect to the element X, where would you position the element Y in the periodic table?

(b) What is the general name of the elements X and Y?

(c) If the atomic number of Y is 80 then what is the atomic number of X?

What mass of ice at 0°C added to 2.1 kg water, will cool it down from 75°C to 25°C? Given Specific heat capacity of water = 4.2 J g⁻¹ °C⁻¹, Specific latent heat of ice = 336 J g⁻¹.

The diagram below shows a cooling curve for a substance :

(a) State the temperatures at which the substance condenses.

(b) The temperature range in which the substance is in liquid state.

(c) Why do we prefer ice to ice-cold water for cooling a drink?