Understand the concepts for finding the change in length of a rod, Kepler's law, and melting of a material.

1. An aluminum rod 15 cm in length is heated from 10 degrees Celsius to 50 degrees Celcius. What is the change in length?

1. 15 cm
2. 8 cm
3. 6 cm
4. None of the above.

2. What is Kepler's first law of planetary orbits?
1. The planets move on ellipses with the Sun at the center of ellipse.
2. The planets revolve around the Earth.
3. The position of the planets foretells the future.
4. The planets move on ellipses with the Sun at one of the foci.

3. In order to completely melt a material,
1. Heat must be added to bring the material to melting temperature and then the latent heat of fusion should be added to change the phase.
2. Heat must be added to make the object expand to the melting volume
3. No heat needs to be added.
4. Stir while adding heat.