SCIENCE PAPER - I (PHYSICS)

State the SI unit of moment of couple?

Name the material used for making a Calorimeter. Why is a Calorimeter made up of thin sheets of the this material?

The melting point of naphthalene is $80°\mathrm{C}$ and the room temperature is $30°\mathrm{C}$. A sample of liquid naphthalene at $100°\mathrm{C}$ is cooled down to the room temperature. Draw a temperature time graph to represent this cooling. In the graph, mark the region which corresponds to the freezing process.

If $104 \mathrm{g}$ of water at $30°\mathrm{C}$is taken in a calorimeter made of copper of mass $42 \mathrm{g}$. When a certain mass of ice at $0°\mathrm{C}$ is added to it, the final steady temperature of the mixture after the ice has melted, was found to be $10°\mathrm{C}$. Find the mass of ice added.  (Specific heat capacity of water = $4.2 \mathrm{J} {\mathrm{g}}^{-1} °{\mathrm{C}}^{-1}$, Specific latent heat of fusion of ice = $336 \mathrm{J} {\mathrm{g}}^{-1}$, Specific heat capacity of copper = $0.4 \mathrm{J} {\mathrm{g}}^{-1}°{\mathrm{C}}^{-1}$)

Draw a neat labeled diagram of an A.C. generator.

Define nuclear fission.

Rewrite and complete the following nuclear reaction by filling in the atomic number of Ba and mass number of Kr:

${}_{92}{}^{235}\mathrm{U} +{}_0{}^1\mathrm{n} \to {}_{\_\_\_}{}^{144}\mathrm{Ba}+{}_{36}{}^{\_\_\_}\mathrm{Kr} + 3 {}_0{}^1\mathrm{n} + \mathrm{Energy}$

The diagram below shows a magnetic needle kept just below the conductor AB which is kept in the North-South direction.

i) In which direction will the needle deflect when the key is closed?

ii) Why is the deflection produced?

iii) What will be the change in the deflection if the magnetic needle is taken just above the conductor AB?

iv) Name one device which works on this principle.