A copper disc is allowed to swing through the two poles of a U-shaped magnet. Explain what you expect to observe.

A five-rupee coin is put on a thick smooth card and place it on a glass tumbler. Now flick the card horizontally striking it hard with your finger at one of its corners. Explain what you observe.

A diamagnetic substance is placed in the middle between two magnetic poles. If allowed to rotate, explain why the specimen comes to rest with its axis perpendicular to the field.

What you mean by families of salts? Explain giving two examples.

After removing the outershell of two eggs in dil. HCl one is plced in distilled water and the other is placed in a saturated solution of NaCl. What will you observe and why?

Two discs of moments of inertia /, and l2 about their respective axes (normal to the disc and passing through the centre), and rotating with angular speeds omega and omega are brought into contact face to face with their axes of rotation coincident, (a) What is the angular speed of the two-disc system? (b) Show that the kinetic energy of the combined system is less than the sum of the initial kinetic energies of the two discs. How do you account for this loss in energy? Take . omega ne omega

• Take a thick sheet of cardboard and make a small hole or narrow slit in its middle. • Allow sunlight to fall on the narrow slit. This gives a narrow beam of white light. • Now, take a glass prism and allow the light from the slit to fall on one of its faces as shown in Fig. • Turn the prism slowly until the light that comes out of it appears on a nearby screen. What do you observe? You will find a beautiful band of colours.

Answer the following questions based on the P-T phase diagram of CO_2 : CO_2 is heated to a temperature 70^@C and compressesothermally. What changes in its properties do you expect to observe?