Define and describe thermal expansion.

A person who is sitting at a distance of 400 m from a source of sound is listening to a sound of 600 Hz. Find the time period between successive compressions from the source?

When you place your ear on rails, it allows you to hear the approach of a train long before you can hear the sound of train in the air. How?

State Soddy and Fajans displacement law.

Calculate the number of moles in
(i) 27g of Al
(ii) 1.51 × 10²³ molecules of NH₄Cl

How is zinc blende concentrated? Explain it with a neat diagram

Write notes on
i) saturated solution
ii) unsaturated solution

How will you classify hydrocarbons?

Man is a mammal and has incisors and canine. Rabbits are mammals but lack canines. Explain.

The complete events of cardiac cycle last for 0.8 sec. What is the timing for each event?

Luteal phase of the menstrual cycle is also called the secretory phase. Give reason.

Explain the process of fertilization in plants?

Two kittens (Leo and Joe) from the same mother were separated and sent to different habitual conditions. Leo was sent to a high mountain wild region and Joe was domesticated and lived in a city. After a good 5 years) it was found that Leo was aggressive and built strong with hunting skills. Leo looked tall with strong legs and muscled structure) whereas Joe was a well mannered cat looked puffy with soft legs.
(i) Do you think habitual condition impact animal characters?
(ii) What acquired characters does Leo inherit?
(iii) Is it true but Leo's offspring would be a hunter?

Write a note an prevention and control of AIDS.

In a biology period, the teacher drew the heart of rabbit on the board and explained its structure and functions. After the class, your friend told you that he finds it difficult to understand the concept and felt he wanted a detailed explanation.
(i) In what way the teaching can be made easily understandable?
(ii) Do you think using technologies like Visual Communication help students to understand the difficult concepts in a simple way?
(iii) By what means the Visual Communication improve the learning ability?